diff --git a/catalog/BUILD b/catalog/BUILD
index 1fdd8967420..9a334733811 100644
--- a/catalog/BUILD
+++ b/catalog/BUILD
@@ -66,7 +66,7 @@ swift_library(
     srcs = native.glob(["MDCCatalog/*.swift"]),
     copts = [
         "-swift-version",
-        "3",
+        "4.2",
     ],
     resources = ["MDCDragons/HeaderView.xib"],
     deps = [
@@ -120,7 +120,7 @@ swift_library(
     srcs = native.glob(["MDCDragons/*.swift"]),
     copts = [
         "-swift-version",
-        "3",
+        "4.2",
     ],
     data = glob(["MDCCatalog/Assets.xcassets/*.imageset/**"]),
     resources = ["MDCDragons/HeaderView.xib"],
diff --git a/catalog/MDCCatalog.xcodeproj/project.pbxproj b/catalog/MDCCatalog.xcodeproj/project.pbxproj
index 91feaeb9c10..f0e8804d50f 100644
--- a/catalog/MDCCatalog.xcodeproj/project.pbxproj
+++ b/catalog/MDCCatalog.xcodeproj/project.pbxproj
@@ -593,7 +593,7 @@
 				PRODUCT_BUNDLE_IDENTIFIER = "com.google.mdc-catalog.MDCActionExtension";
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				SKIP_INSTALL = YES;
-				SWIFT_VERSION = 3.0;
+				SWIFT_VERSION = 4.2;
 			};
 			name = Debug;
 		};
@@ -613,7 +613,7 @@
 				PRODUCT_BUNDLE_IDENTIFIER = "com.google.mdc-catalog.MDCActionExtension";
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				SKIP_INSTALL = YES;
-				SWIFT_VERSION = 3.0;
+				SWIFT_VERSION = 4.2;
 			};
 			name = Release;
 		};
@@ -738,7 +738,7 @@
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				SWIFT_OBJC_BRIDGING_HEADER = "MDCCatalog/MDCCatalog-Bridging-Header.h";
 				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
-				SWIFT_VERSION = 3.0;
+				SWIFT_VERSION = 4.2;
 			};
 			name = Debug;
 		};
@@ -756,7 +756,7 @@
 				PRODUCT_BUNDLE_IDENTIFIER = com.google.MDCCatalog;
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				SWIFT_OBJC_BRIDGING_HEADER = "MDCCatalog/MDCCatalog-Bridging-Header.h";
-				SWIFT_VERSION = 3.0;
+				SWIFT_VERSION = 4.2;
 			};
 			name = Release;
 		};
diff --git a/catalog/MDCCatalog/AppDelegate.swift b/catalog/MDCCatalog/AppDelegate.swift
index 57b5fce3fdb..107dc1c966a 100644
--- a/catalog/MDCCatalog/AppDelegate.swift
+++ b/catalog/MDCCatalog/AppDelegate.swift
@@ -32,7 +32,7 @@ class AppDelegate: UIResponder, UIApplicationDelegate, MDCAppBarNavigationContro
   let navigationController = MDCAppBarNavigationController()
 
   func application(_ application: UIApplication, didFinishLaunchingWithOptions
-                   launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
+                   launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
     self.window = MDCCatalogWindow(frame: UIScreen.main.bounds)
 
     // The navigation tree will only take examples that implement
@@ -66,9 +66,9 @@ class AppDelegate: UIResponder, UIApplicationDelegate, MDCAppBarNavigationContro
     return true
   }
 
-  func themeDidChange(notification: NSNotification) {
+  @objc func themeDidChange(notification: NSNotification) {
     let colorScheme = AppTheme.globalTheme.colorScheme
-    for viewController in navigationController.childViewControllers {
+    for viewController in navigationController.children {
       guard let appBar = navigationController.appBar(for: viewController) else {
         continue
       }
@@ -104,7 +104,7 @@ protocol CatalogAppBarInjectee {
 }
 
 extension UINavigationController {
-  func presentMenu() {
+  @objc func presentMenu() {
     let menuViewController = MDCMenuViewController(style: .plain)
     let bottomSheet = MDCBottomSheetController(contentViewController: menuViewController)
     self.present(bottomSheet, animated: true, completion: nil)
diff --git a/catalog/MDCCatalog/MDCCatalogCollectionViewCell.swift b/catalog/MDCCatalog/MDCCatalogCollectionViewCell.swift
index 380627545a2..ecf462b5727 100644
--- a/catalog/MDCCatalog/MDCCatalogCollectionViewCell.swift
+++ b/catalog/MDCCatalog/MDCCatalogCollectionViewCell.swift
@@ -38,7 +38,9 @@ class MDCCatalogCollectionViewCell: UICollectionViewCell {
     contentView.clipsToBounds = true
     contentView.addSubview(tile)
     self.isAccessibilityElement = true
-    self.accessibilityTraits |= UIAccessibilityTraitButton
+    let rawAccessibilityTraits =
+      accessibilityTraits.rawValue | UIAccessibilityTraits.button.rawValue
+    self.accessibilityTraits = UIAccessibilityTraits(rawValue: rawAccessibilityTraits)
 
     updateTheme()
 
@@ -85,7 +87,7 @@ class MDCCatalogCollectionViewCell: UICollectionViewCell {
     label.textColor = AppTheme.globalTheme.colorScheme.onBackgroundColor
   }
 
-  func themeDidChange(notification: NSNotification) {
+  @objc func themeDidChange(notification: NSNotification) {
     updateTheme()
   }
 
diff --git a/catalog/MDCCatalog/MDCCatalogComponentsController.swift b/catalog/MDCCatalog/MDCCatalogComponentsController.swift
index 534a336426c..f3c14367476 100644
--- a/catalog/MDCCatalog/MDCCatalogComponentsController.swift
+++ b/catalog/MDCCatalog/MDCCatalogComponentsController.swift
@@ -27,7 +27,7 @@ import MaterialComponents.MaterialTypography
 
 import UIKit
 
-class MDCCatalogComponentsController: UICollectionViewController, MDCInkTouchControllerDelegate {
+class MDCCatalogComponentsController: UICollectionViewController, UICollectionViewDelegateFlowLayout, MDCInkTouchControllerDelegate {
 
   fileprivate struct Constants {
     static let headerScrollThreshold: CGFloat = 30
@@ -94,7 +94,7 @@ class MDCCatalogComponentsController: UICollectionViewController, MDCInkTouchCon
 
     title = "Material Components for iOS"
 
-    addChildViewController(headerViewController)
+    addChild(headerViewController)
 
     headerViewController.isTopLayoutGuideAdjustmentEnabled = true
     headerViewController.inferTopSafeAreaInsetFromViewController = true
@@ -115,7 +115,7 @@ class MDCCatalogComponentsController: UICollectionViewController, MDCInkTouchCon
       object: nil)
   }
 
-  func themeDidChange(notification: NSNotification) {
+  @objc func themeDidChange(notification: NSNotification) {
     let colorScheme = AppTheme.globalTheme.colorScheme
     MDCFlexibleHeaderColorThemer.applySemanticColorScheme(colorScheme,
                                                           to: headerViewController.headerView)
@@ -198,18 +198,12 @@ class MDCCatalogComponentsController: UICollectionViewController, MDCInkTouchCon
     }
 
     view.addSubview(headerViewController.view)
-    #if swift(>=4.2)
     headerViewController.didMove(toParent: self)
-    #else
-    headerViewController.didMove(toParentViewController: self)
-    #endif
 
     collectionView?.accessibilityIdentifier = "collectionView"
-#if swift(>=3.2)
     if #available(iOS 11.0, *) {
       collectionView?.contentInsetAdjustmentBehavior = .always
     }
-#endif
   }
 
   override func viewWillAppear(_ animated: Bool) {
@@ -223,15 +217,14 @@ class MDCCatalogComponentsController: UICollectionViewController, MDCInkTouchCon
     collectionView?.collectionViewLayout.invalidateLayout()
   }
 
-  override var childViewControllerForStatusBarStyle: UIViewController? {
+  override var childForStatusBarStyle: UIViewController? {
     return headerViewController
   }
 
-  override var childViewControllerForStatusBarHidden: UIViewController? {
+  override var childForStatusBarHidden: UIViewController? {
     return headerViewController
   }
 
-#if swift(>=3.2)
   @available(iOS 11, *)
   override func viewSafeAreaInsetsDidChange() {
     // Re-constraint the title label to account for changes in safeAreaInsets's left and right.
@@ -239,7 +232,6 @@ class MDCCatalogComponentsController: UICollectionViewController, MDCInkTouchCon
     menuButtonRightPaddingConstraint?.constant = -1 * (Constants.inset + view.safeAreaInsets.right)
     menuTopPaddingConstraint?.constant = Constants.inset + view.safeAreaInsets.top
   }
-#endif
 
   func setupFlexibleHeaderContentConstraints() {
 
@@ -364,14 +356,12 @@ class MDCCatalogComponentsController: UICollectionViewController, MDCInkTouchCon
 
   func collectionView(_ collectionView: UICollectionView,
                       layout collectionViewLayout: UICollectionViewLayout,
-                      sizeForItemAtIndexPath indexPath: IndexPath) -> CGSize {
+                      sizeForItemAt indexPath: IndexPath) -> CGSize {
     let dividerWidth: CGFloat = 1
     var safeInsets: CGFloat = 0
-#if swift(>=3.2)
     if #available(iOS 11, *) {
       safeInsets = view.safeAreaInsets.left + view.safeAreaInsets.right
     }
-#endif
     var cellWidthHeight: CGFloat
 
     // iPhones have 2 columns in portrait and 3 in landscape
diff --git a/catalog/MDCCatalog/MDCCatalogDebugAlert.swift b/catalog/MDCCatalog/MDCCatalogDebugAlert.swift
index b891ea8bb1e..2fc0fd08a4c 100644
--- a/catalog/MDCCatalog/MDCCatalogDebugAlert.swift
+++ b/catalog/MDCCatalog/MDCCatalogDebugAlert.swift
@@ -195,7 +195,7 @@ class MDCCatalogDebugDismissCell: UICollectionViewCell {
     label.text = "DISMISS"
     label.textAlignment = .center
     isAccessibilityElement = true
-    accessibilityTraits = UIAccessibilityTraitButton
+    accessibilityTraits = .button
     accessibilityLabel = label.text
     contentView.addSubview(label)
   }
diff --git a/catalog/MDCCatalog/MDCCatalogTileView.swift b/catalog/MDCCatalog/MDCCatalogTileView.swift
index 307649423e1..735884344bd 100644
--- a/catalog/MDCCatalog/MDCCatalogTileView.swift
+++ b/catalog/MDCCatalog/MDCCatalogTileView.swift
@@ -54,7 +54,7 @@ class MDCCatalogTileView: UIView {
     super.init(coder: aDecoder)
   }
 
-  func themeDidChange(notification: NSNotification) {
+  @objc func themeDidChange(notification: NSNotification) {
     imageCache.removeAllObjects()
   }
 
diff --git a/catalog/MDCCatalog/MDCDebugSafeAreaInsetsView.swift b/catalog/MDCCatalog/MDCDebugSafeAreaInsetsView.swift
index 327bff08f1d..ace6f67ff11 100644
--- a/catalog/MDCCatalog/MDCDebugSafeAreaInsetsView.swift
+++ b/catalog/MDCCatalog/MDCDebugSafeAreaInsetsView.swift
@@ -37,20 +37,16 @@ class MDCDebugSafeAreaInsetsView: UIView {
     fatalError("init(coder:) has not been implemented")
   }
 
-#if swift(>=3.2)
   override open func safeAreaInsetsDidChange() {
     setNeedsLayout()
     layoutIfNeeded()
   }
-#endif
 
   override func layoutSubviews() {
     var safeAreaInsets = UIEdgeInsets.zero
-#if swift(>=3.2)
     if #available(iOS 11, *) {
       safeAreaInsets = self.safeAreaInsets
     }
-#endif
 
     let width = frame.width
     let height = frame.height
diff --git a/catalog/MDCCatalog/MDCNodeListViewController.swift b/catalog/MDCCatalog/MDCNodeListViewController.swift
index 0ecdc992ac9..b3864c4884c 100644
--- a/catalog/MDCCatalog/MDCNodeListViewController.swift
+++ b/catalog/MDCCatalog/MDCNodeListViewController.swift
@@ -30,7 +30,7 @@ class NodeViewTableViewDemoCell: UITableViewCell {
 
   let label = UILabel()
 
-  override init(style: UITableViewCellStyle, reuseIdentifier: String?) {
+  override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
     super.init(style: .subtitle, reuseIdentifier: reuseIdentifier)
     textLabel!.font = MDCTypography.subheadFont()
     imageView!.image = UIImage(named: "Demo")
@@ -95,7 +95,7 @@ class NodeViewTableViewPrimaryDemoCell: UITableViewCell {
 
   let containedButton = MDCButton()
 
-  override init(style: UITableViewCellStyle, reuseIdentifier: String?) {
+  override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
     super.init(style: style, reuseIdentifier: reuseIdentifier)
     setupContainedButton()
   }
@@ -213,14 +213,10 @@ class MDCNodeListViewController: CBCNodeListViewController {
     additionalExamplesSectionHeader = createAdditionalExamplesSectionHeader()
     self.tableView.backgroundColor = UIColor.white
     self.tableView.separatorStyle = .none
-    self.tableView.sectionHeaderHeight = UITableViewAutomaticDimension
+    self.tableView.sectionHeaderHeight = UITableView.automaticDimension
 
     var charactersCount = 0
-    #if swift(>=3.2)
-      charactersCount = node.title.count
-    #else
-      charactersCount = node.title.characters.count
-    #endif
+    charactersCount = node.title.count
     if charactersCount > 0 {
       self.tableView.accessibilityIdentifier = "Table" + node.title
     } else {
@@ -239,7 +235,7 @@ class MDCNodeListViewController: CBCNodeListViewController {
     self.navigationController?.setNavigationBarHidden(true, animated: animated)
   }
 
-  func themeDidChange(notification: NSNotification) {
+  @objc func themeDidChange(notification: NSNotification) {
     setNeedsStatusBarAppearanceUpdate()
     self.tableView.reloadData()
   }
@@ -298,7 +294,7 @@ extension MDCNodeListViewController {
     sectionTitleLabel.translatesAutoresizingMaskIntoConstraints = false
     sectionTitleLabel.text = sectionNames[1]
     sectionTitleLabel.numberOfLines = 0
-    sectionTitleLabel.setContentCompressionResistancePriority(1000, for: .vertical)
+    sectionTitleLabel.setContentCompressionResistancePriority(.required, for: .vertical)
 
     sectionView.addSubview(lineDivider)
     sectionView.addSubview(sectionTitleLabel)
@@ -368,7 +364,6 @@ extension MDCNodeListViewController {
         constant: self.padding).isActive = true
     }
     // Title Label to Section View
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       // Align to the safe area insets.
       sectionTitleLabel.leadingAnchor
@@ -380,9 +375,6 @@ extension MDCNodeListViewController {
     } else {
       preiOS11Behavior()
     }
-    #else
-    preiOS11Behavior()
-    #endif
 
      NSLayoutConstraint(
       item: sectionView,
@@ -405,7 +397,7 @@ extension MDCNodeListViewController {
     sectionTitleLabel.translatesAutoresizingMaskIntoConstraints = false
     sectionTitleLabel.text = sectionNames[0]
     sectionTitleLabel.numberOfLines = 0
-    sectionTitleLabel.setContentCompressionResistancePriority(1000, for: .vertical)
+    sectionTitleLabel.setContentCompressionResistancePriority(.required, for: .vertical)
     mainSectionHeaderTitleLabel = sectionTitleLabel
 
     let descriptionLabel = UILabel()
@@ -413,14 +405,14 @@ extension MDCNodeListViewController {
 
     let paragraphStyle = NSMutableParagraphStyle()
     paragraphStyle.lineSpacing = descriptionLineHeight - descriptionLabel.font.lineHeight
-    let attrs = [NSParagraphStyleAttributeName: paragraphStyle]
+    let attrs = [NSAttributedString.Key.paragraphStyle: paragraphStyle]
 
     descriptionLabel.attributedText =
         NSAttributedString(string:componentDescription, attributes:attrs)
     descriptionLabel.alpha = MDCTypography.body1FontOpacity()
     descriptionLabel.translatesAutoresizingMaskIntoConstraints = false
     descriptionLabel.numberOfLines = 0
-    descriptionLabel.setContentCompressionResistancePriority(1000, for: .vertical)
+    descriptionLabel.setContentCompressionResistancePriority(.required, for: .vertical)
     mainSectionHeaderDescriptionLabel = descriptionLabel
 
     sectionView.addSubview(sectionTitleLabel)
@@ -445,7 +437,6 @@ extension MDCNodeListViewController {
         multiplier: 1.0,
         constant: self.padding).isActive = true
     }
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       // Align to the safe area insets.
       sectionTitleLabel.leadingAnchor
@@ -457,9 +448,6 @@ extension MDCNodeListViewController {
     } else {
       preiOS11Behavior()
     }
-    #else
-    preiOS11Behavior()
-    #endif
 
     NSLayoutConstraint(
       item: sectionTitleLabel,
@@ -555,7 +543,7 @@ extension MDCNodeListViewController {
     return true
   }
 
-  func primaryDemoButtonClicked () {
+  @objc func primaryDemoButtonClicked () {
     let indexPath = IndexPath(row: 0, section: Section.description.rawValue)
     self.tableView(self.tableView, didSelectRowAt: indexPath)
   }
diff --git a/catalog/MDCDragons.xcodeproj/project.pbxproj b/catalog/MDCDragons.xcodeproj/project.pbxproj
index f8e4b5b4d31..69d5e94e86f 100644
--- a/catalog/MDCDragons.xcodeproj/project.pbxproj
+++ b/catalog/MDCDragons.xcodeproj/project.pbxproj
@@ -376,7 +376,7 @@
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks";
 				PRODUCT_BUNDLE_IDENTIFIER = com.google.MDCDragons;
 				PRODUCT_NAME = "$(TARGET_NAME)";
-				SWIFT_VERSION = 3.0;
+				SWIFT_VERSION = 4.2;
 				TARGETED_DEVICE_FAMILY = "1,2";
 			};
 			name = Debug;
@@ -392,7 +392,7 @@
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks";
 				PRODUCT_BUNDLE_IDENTIFIER = com.google.MDCDragons;
 				PRODUCT_NAME = "$(TARGET_NAME)";
-				SWIFT_VERSION = 3.0;
+				SWIFT_VERSION = 4.2;
 				TARGETED_DEVICE_FAMILY = "1,2";
 			};
 			name = Release;
diff --git a/catalog/MDCDragons/AppDelegate.swift b/catalog/MDCDragons/AppDelegate.swift
index 0991ba9d623..d3388ad5d53 100644
--- a/catalog/MDCDragons/AppDelegate.swift
+++ b/catalog/MDCDragons/AppDelegate.swift
@@ -21,7 +21,7 @@ import CatalogByConvention
 class AppDelegate: UIResponder, UIApplicationDelegate {
   var window: UIWindow?
 
-  func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
+  func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
     self.window = UIWindow(frame: UIScreen.main.bounds)
     UIApplication.shared.statusBarStyle = .lightContent
     let tree = CBCCreateNavigationTree()
diff --git a/catalog/MDCDragons/MDCDragonsController.swift b/catalog/MDCDragons/MDCDragonsController.swift
index 335ac64c584..22c185fe71d 100644
--- a/catalog/MDCDragons/MDCDragonsController.swift
+++ b/catalog/MDCDragons/MDCDragonsController.swift
@@ -92,7 +92,7 @@ class MDCDragonsController: UIViewController,
   override func viewDidLoad() {
     super.viewDidLoad()
     title = "Material Dragons"
-    addChildViewController(headerViewController)
+    addChild(headerViewController)
     headerViewController.headerView.minMaxHeightIncludesSafeArea = false
     headerViewController.headerView.maximumHeight = Constants.headerViewMaxHeight
     headerViewController.headerView.minimumHeight = Constants.headerViewMinHeight
@@ -105,32 +105,26 @@ class MDCDragonsController: UIViewController,
     view.addSubview(tableView)
     view.backgroundColor = Constants.bgColor
 
-    #if swift(>=3.2)
-      if #available(iOS 11, *) {
-        tableView.translatesAutoresizingMaskIntoConstraints = false
+    if #available(iOS 11, *) {
+      tableView.translatesAutoresizingMaskIntoConstraints = false
 
-        let guide = view.safeAreaLayoutGuide
-        NSLayoutConstraint.activate([tableView.leftAnchor.constraint(equalTo: guide.leftAnchor),
-                                    tableView.rightAnchor.constraint(equalTo: guide.rightAnchor),
-                                    tableView.topAnchor.constraint(equalTo: view.topAnchor),
-                                    tableView.bottomAnchor.constraint(equalTo: guide.bottomAnchor)])
-      } else {
-        preiOS11Constraints()
-      }
-    #else
+      let guide = view.safeAreaLayoutGuide
+      NSLayoutConstraint.activate([tableView.leftAnchor.constraint(equalTo: guide.leftAnchor),
+                                   tableView.rightAnchor.constraint(equalTo: guide.rightAnchor),
+                                   tableView.topAnchor.constraint(equalTo: view.topAnchor),
+                                   tableView.bottomAnchor.constraint(equalTo: guide.bottomAnchor)])
+    } else {
       preiOS11Constraints()
-    #endif
+    }
 
     setupHeaderView()
     let tapgesture = UITapGestureRecognizer(target: self, action: #selector(dismissKeyboard))
     tapgesture.delegate = self
     view.addGestureRecognizer(tapgesture)
 
-    #if swift(>=3.2)
-      if #available(iOS 11.0, *) {
-        tableView.contentInsetAdjustmentBehavior = .always
-      }
-    #endif
+    if #available(iOS 11.0, *) {
+      tableView.contentInsetAdjustmentBehavior = .always
+    }
   }
 
   func preiOS11Constraints() {
@@ -148,7 +142,7 @@ class MDCDragonsController: UIViewController,
     headerViewController.headerView.backgroundColor = Constants.headerColor
     headerViewController.headerView.trackingScrollView = tableView
     view.addSubview(headerViewController.view)
-    headerViewController.didMove(toParentViewController: self)
+    headerViewController.didMove(toParent: self)
   }
 
   func adjustLogoForScrollView(_ scrollView: UIScrollView) {
@@ -165,11 +159,11 @@ class MDCDragonsController: UIViewController,
     navigationController?.setNavigationBarHidden(true, animated: animated)
   }
 
-  override var childViewControllerForStatusBarStyle: UIViewController? {
+  override var childForStatusBarStyle: UIViewController? {
     return headerViewController
   }
 
-  override var childViewControllerForStatusBarHidden: UIViewController? {
+  override var childForStatusBarHidden: UIViewController? {
     return headerViewController
   }
 
@@ -251,8 +245,8 @@ class MDCDragonsController: UIViewController,
       container.appBar.headerViewController.headerView.backgroundColor = headerViewController.headerView.backgroundColor
       container.appBar.navigationBar.tintColor = .white
       container.appBar.navigationBar.titleTextAttributes =
-        [ NSForegroundColorAttributeName: UIColor.white,
-          NSFontAttributeName: UIFont.systemFont(ofSize: 16) ]
+        [ .foregroundColor: UIColor.white,
+          .font: UIFont.systemFont(ofSize: 16) ]
       container.isTopLayoutGuideAdjustmentEnabled = true
       vc.title = nodeData.node.title
 
@@ -381,17 +375,17 @@ extension MDCDragonsController {
     NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillChangeFrame(notification:)), name: .MDCKeyboardWatcherKeyboardWillChangeFrame, object: nil)
   }
 
-  func keyboardWillShow(notification: NSNotification) {
+  @objc func keyboardWillShow(notification: NSNotification) {
     guard let userInfo = notification.userInfo else { return }
     updateScrollViewWithKeyboardNotificationUserInfo(userInfo: userInfo)
   }
 
-  func keyboardWillHide(notification: NSNotification) {
+  @objc func keyboardWillHide(notification: NSNotification) {
     guard let userInfo = notification.userInfo else { return }
     updateScrollViewWithKeyboardNotificationUserInfo(userInfo: userInfo)
   }
 
-  func keyboardWillChangeFrame(notification: NSNotification) {
+  @objc func keyboardWillChangeFrame(notification: NSNotification) {
     guard let userInfo = notification.userInfo else { return }
     updateScrollViewWithKeyboardNotificationUserInfo(userInfo: userInfo)
   }
diff --git a/catalog/MDCDragons/MDCDragonsTableViewCell.swift b/catalog/MDCDragons/MDCDragonsTableViewCell.swift
index c6c7efe568d..4785fcc5bcd 100644
--- a/catalog/MDCDragons/MDCDragonsTableViewCell.swift
+++ b/catalog/MDCDragons/MDCDragonsTableViewCell.swift
@@ -33,7 +33,7 @@ class MDCDragonsTableViewCell: UITableViewCell {
     return button
   }()
 
-  override init(style: UITableViewCellStyle, reuseIdentifier: String?) {
+  override init(style: UITableViewCell.CellStyle, reuseIdentifier: String?) {
     super.init(style: style, reuseIdentifier: reuseIdentifier)
     self.accessoryView = self.defaultButton
   }
diff --git a/components/ActionSheet/BUILD b/components/ActionSheet/BUILD
index cb58f351adb..bdf6fcfe711 100644
--- a/components/ActionSheet/BUILD
+++ b/components/ActionSheet/BUILD
@@ -113,7 +113,7 @@ swift_library(
     srcs = glob(["tests/unit/*.swift"]),
     copts = [
         "-swift-version",
-        "3",
+        "4.2",
     ],
     deps = [
         ":ActionSheet",
@@ -126,7 +126,7 @@ swift_library(
     srcs = glob(["tests/unit/ColorThemer/*.swift"]),
     copts = [
         "-swift-version",
-        "3",
+        "4.2",
     ],
     deps = [
         ":ActionSheet",
diff --git a/components/ActionSheet/tests/unit/ActionSheetTest.swift b/components/ActionSheet/tests/unit/ActionSheetTest.swift
index d1d5db74a2c..0aa000c3cbb 100644
--- a/components/ActionSheet/tests/unit/ActionSheetTest.swift
+++ b/components/ActionSheet/tests/unit/ActionSheetTest.swift
@@ -67,7 +67,7 @@ class ActionSheetTest: XCTestCase {
     actionSheet.addAction(action)
 
     // Then
-    let tableView = actionSheet.view.subviews.flatMap{ $0 as? UITableView }.first
+    let tableView = actionSheet.view.subviews.compactMap { $0 as? UITableView }.first
     if let table = tableView {
       XCTAssertEqual(table.numberOfRows(inSection: section), rowCount)
       if let dataSource = table.dataSource {
diff --git a/components/ActivityIndicator/BUILD b/components/ActivityIndicator/BUILD
index 8ae78cee7b0..612655b2a54 100644
--- a/components/ActivityIndicator/BUILD
+++ b/components/ActivityIndicator/BUILD
@@ -68,7 +68,7 @@ swift_library(
     srcs = glob(["tests/unit/*.swift"]),
     copts = [
         "-swift-version",
-        "3",
+        "4.2",
     ],
     visibility = ["//visibility:private"],
     deps = [
diff --git a/components/AnimationTiming/examples/AnimationTimingSwiftExampleViewController.swift b/components/AnimationTiming/examples/AnimationTimingSwiftExampleViewController.swift
index fbd4576cad8..25688483f17 100644
--- a/components/AnimationTiming/examples/AnimationTimingSwiftExampleViewController.swift
+++ b/components/AnimationTiming/examples/AnimationTimingSwiftExampleViewController.swift
@@ -55,8 +55,8 @@ class AnimationTimingSwiftExampleViewController: UIViewController {
 
    }
 
-   func playAnimations() {
-      let linearCurve: CAMediaTimingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionLinear)
+   @objc func playAnimations() {
+      let linearCurve: CAMediaTimingFunction = CAMediaTimingFunction(name: CAMediaTimingFunctionName.linear)
       applyAnimation(toView: linearView, withTimingFunction: linearCurve)
 
       if let materialStandard = CAMediaTimingFunction.mdc_function(withType: .standard) {
diff --git a/components/AppBar/BUILD b/components/AppBar/BUILD
index ce215d9c6cc..f3228de7199 100644
--- a/components/AppBar/BUILD
+++ b/components/AppBar/BUILD
@@ -138,7 +138,7 @@ swift_library(
     srcs = glob(["tests/unit/*.swift"]),
     copts = [
         "-swift-version",
-        "3",
+        "4.2",
     ],
     visibility = ["//visibility:private"],
     deps = [
diff --git a/components/AppBar/examples/AppBarAnimatedGlitchExample.swift b/components/AppBar/examples/AppBarAnimatedGlitchExample.swift
index 6d24e1439c8..39fb6f6c9cb 100644
--- a/components/AppBar/examples/AppBarAnimatedGlitchExample.swift
+++ b/components/AppBar/examples/AppBarAnimatedGlitchExample.swift
@@ -73,11 +73,7 @@ class AppBarAnimatedJumpExample: UIViewController {
     view.isOpaque = false
     view.backgroundColor = colorScheme.backgroundColor
     view.addSubview(appBarViewController.view)
-    #if swift(>=4.2)
     appBarViewController.didMove(toParent: self)
-    #else
-    appBarViewController.didMove(toParentViewController: self)
-    #endif
 
     switchToTab(tabs[0], animated: false)
   }
@@ -90,7 +86,7 @@ class AppBarAnimatedJumpExample: UIViewController {
     let removeOld: (() -> Void)
     let animateOut: (() -> Void)
     if let currentTab = currentTab {
-      currentTab.willMove(toParentViewController: nil)
+      currentTab.willMove(toParent: nil)
 
       animateOut = {
         currentTab.view.alpha = 0
@@ -99,7 +95,7 @@ class AppBarAnimatedJumpExample: UIViewController {
       removeOld = {
         currentTab.headerView = nil
         currentTab.view.removeFromSuperview()
-        currentTab.removeFromParentViewController()
+        currentTab.removeFromParent()
       }
     } else {
       removeOld = {}
@@ -113,12 +109,8 @@ class AppBarAnimatedJumpExample: UIViewController {
 
     // Show new tab.
     view.addSubview(tab.view)
-    view.sendSubview(toBack: tab.view)
-    #if swift(>=4.2)
+    view.sendSubviewToBack(tab.view)
     tab.didMove(toParent: self)
-    #else
-    tab.didMove(toParentViewController: self)
-    #endif
     tab.headerView = self.appBarViewController.headerView
 
     tab.view.alpha = 0
@@ -162,7 +154,7 @@ class AppBarAnimatedJumpExample: UIViewController {
   private func makeAppBar() -> MDCAppBarViewController {
     let appBarViewController = MDCAppBarViewController()
 
-    addChildViewController(appBarViewController)
+    addChild(appBarViewController)
 
     // Give the tab bar enough height to accomodate all possible item appearances.
     appBarViewController.headerView.minMaxHeightIncludesSafeArea = false
@@ -178,7 +170,7 @@ class AppBarAnimatedJumpExample: UIViewController {
     return appBarViewController
   }
 
-  override var childViewControllerForStatusBarStyle: UIViewController? {
+  override var childForStatusBarStyle: UIViewController? {
     return appBarViewController
   }
 }
diff --git a/components/AppBar/examples/AppBarGlitchExample.swift b/components/AppBar/examples/AppBarGlitchExample.swift
index 9f8428cbeef..b6419bbcd00 100644
--- a/components/AppBar/examples/AppBarGlitchExample.swift
+++ b/components/AppBar/examples/AppBarGlitchExample.swift
@@ -69,11 +69,7 @@ class AppBarJumpExample: UIViewController {
 
     view.backgroundColor = colorScheme.backgroundColor
     view.addSubview(appBarViewController.view)
-    #if swift(>=4.2)
     appBarViewController.didMove(toParent: self)
-    #else
-    appBarViewController.didMove(toParentViewController: self)
-    #endif
 
     switchToTab(firstTab)
   }
@@ -84,9 +80,9 @@ class AppBarJumpExample: UIViewController {
 
     if let currentTab = currentTab {
       currentTab.headerView = nil
-      currentTab.willMove(toParentViewController: nil)
+      currentTab.willMove(toParent: nil)
       currentTab.view.removeFromSuperview()
-      currentTab.removeFromParentViewController()
+      currentTab.removeFromParent()
     }
 
     if let tabView = tab.view {
@@ -95,12 +91,8 @@ class AppBarJumpExample: UIViewController {
     }
 
     view.addSubview(tab.view)
-    view.sendSubview(toBack: tab.view)
-    #if swift(>=4.2)
+    view.sendSubviewToBack(tab.view)
     tab.didMove(toParent: self)
-    #else
-    tab.didMove(toParentViewController: self)
-    #endif
 
     tab.headerView = appBarViewController.headerView
 
@@ -123,7 +115,7 @@ class AppBarJumpExample: UIViewController {
   private func makeAppBar() -> MDCAppBarViewController {
     let appBarViewController = MDCAppBarViewController()
 
-    addChildViewController(appBarViewController)
+    addChild(appBarViewController)
 
     // Give the tab bar enough height to accomodate all possible item appearances.
     appBarViewController.headerView.minMaxHeightIncludesSafeArea = false
@@ -139,7 +131,7 @@ class AppBarJumpExample: UIViewController {
     return appBarViewController
   }
 
-  override var childViewControllerForStatusBarStyle: UIViewController? {
+  override var childForStatusBarStyle: UIViewController? {
     return appBarViewController
   }
 }
diff --git a/components/AppBar/examples/AppBarImageryExample.swift b/components/AppBar/examples/AppBarImageryExample.swift
index 805ef71e7cf..405b75e42a6 100644
--- a/components/AppBar/examples/AppBarImageryExample.swift
+++ b/components/AppBar/examples/AppBarImageryExample.swift
@@ -60,11 +60,7 @@ class AppBarImagerySwiftExample: UITableViewController {
     headerView.trackingScrollView = self.tableView
 
     view.addSubview(appBarViewController.view)
-    #if swift(>=4.2)
     appBarViewController.didMove(toParent: self)
-    #else
-    appBarViewController.didMove(toParentViewController: self)
-    #endif
   }
 
   override var preferredStatusBarStyle: UIStatusBarStyle {
@@ -83,7 +79,7 @@ class AppBarImagerySwiftExample: UITableViewController {
     appBarViewController.inferTopSafeAreaInsetFromViewController = true
     appBarViewController.headerView.minMaxHeightIncludesSafeArea = false
 
-    self.addChildViewController(appBarViewController)
+    self.addChild(appBarViewController)
   }
 
   required init?(coder aDecoder: NSCoder) {
diff --git a/components/AppBar/examples/AppBarInheritedAnimatedJumpExample.swift b/components/AppBar/examples/AppBarInheritedAnimatedJumpExample.swift
index 0dd484bc17a..957e8cd014b 100644
--- a/components/AppBar/examples/AppBarInheritedAnimatedJumpExample.swift
+++ b/components/AppBar/examples/AppBarInheritedAnimatedJumpExample.swift
@@ -73,11 +73,7 @@ class AppBarInheritedAnimatedJumpExample: UIViewController {
     view.isOpaque = false
     view.backgroundColor = colorScheme.backgroundColor
     view.addSubview(appBarViewController.view)
-    #if swift(>=4.2)
     appBarViewController.didMove(toParent: self)
-    #else
-    appBarViewController.didMove(toParentViewController: self)
-    #endif
 
     switchToTab(tabs[0], animated: false)
   }
@@ -90,7 +86,7 @@ class AppBarInheritedAnimatedJumpExample: UIViewController {
     let removeOld: (() -> Void)
     let animateOut: (() -> Void)
     if let currentTab = currentTab {
-      currentTab.willMove(toParentViewController: nil)
+      currentTab.willMove(toParent: nil)
 
       animateOut = {
         currentTab.view.alpha = 0
@@ -99,7 +95,7 @@ class AppBarInheritedAnimatedJumpExample: UIViewController {
       removeOld = {
         currentTab.headerView = nil
         currentTab.view.removeFromSuperview()
-        currentTab.removeFromParentViewController()
+        currentTab.removeFromParent()
       }
     } else {
       removeOld = {}
@@ -113,12 +109,8 @@ class AppBarInheritedAnimatedJumpExample: UIViewController {
 
     // Show new tab.
     view.addSubview(tab.view)
-    view.sendSubview(toBack: tab.view)
-    #if swift(>=4.2)
+    view.sendSubviewToBack(tab.view)
     tab.didMove(toParent: self)
-    #else
-    tab.didMove(toParentViewController: self)
-    #endif
     tab.headerView = self.appBarViewController.headerView
 
     tab.view.alpha = 0
@@ -162,7 +154,7 @@ class AppBarInheritedAnimatedJumpExample: UIViewController {
   private func makeAppBar() -> MDCAppBarViewController {
     let appBarViewController = MDCAppBarViewController()
 
-    addChildViewController(appBarViewController)
+    addChild(appBarViewController)
 
     // Give the tab bar enough height to accommodate all possible item appearances.
     appBarViewController.headerView.minMaxHeightIncludesSafeArea = false
@@ -178,7 +170,7 @@ class AppBarInheritedAnimatedJumpExample: UIViewController {
     return appBarViewController
   }
 
-  override var childViewControllerForStatusBarStyle: UIViewController? {
+  override var childForStatusBarStyle: UIViewController? {
     return appBarViewController
   }
 }
diff --git a/components/AppBar/examples/AppBarInterfaceBuilderExampleController.swift b/components/AppBar/examples/AppBarInterfaceBuilderExampleController.swift
index 64d61757d4d..43300fa0a05 100644
--- a/components/AppBar/examples/AppBarInterfaceBuilderExampleController.swift
+++ b/components/AppBar/examples/AppBarInterfaceBuilderExampleController.swift
@@ -45,7 +45,7 @@ class AppBarInterfaceBuilderSwiftExample: UIViewController, UIScrollViewDelegate
     appBarViewController.inferTopSafeAreaInsetFromViewController = true
     appBarViewController.headerView.minMaxHeightIncludesSafeArea = false
 
-    addChildViewController(appBarViewController)
+    addChild(appBarViewController)
   }
 
   override func viewDidLoad() {
@@ -59,11 +59,7 @@ class AppBarInterfaceBuilderSwiftExample: UIViewController, UIScrollViewDelegate
     appBarViewController.headerView.trackingScrollView = scrollView
 
     view.addSubview(appBarViewController.view)
-    #if swift(>=4.2)
     appBarViewController.didMove(toParent: self)
-    #else
-    appBarViewController.didMove(toParentViewController: self)
-    #endif
   }
 
   override var preferredStatusBarStyle: UIStatusBarStyle {
diff --git a/components/AppBar/examples/AppBarManualTabsExample.swift b/components/AppBar/examples/AppBarManualTabsExample.swift
index 064ca0337b6..32f6f3a51e9 100644
--- a/components/AppBar/examples/AppBarManualTabsExample.swift
+++ b/components/AppBar/examples/AppBarManualTabsExample.swift
@@ -73,11 +73,7 @@ class AppBarManualTabsExample: UIViewController {
 
     view.backgroundColor = colorScheme.backgroundColor
     view.addSubview(appBarViewController.view)
-    #if swift(>=4.2)
     appBarViewController.didMove(toParent: self)
-    #else
-    appBarViewController.didMove(toParentViewController: self)
-    #endif
 
     switchToTab(firstTab)
   }
@@ -87,9 +83,9 @@ class AppBarManualTabsExample: UIViewController {
 
     if let currentTab = currentTab {
       currentTab.headerView = nil
-      currentTab.willMove(toParentViewController: nil)
+      currentTab.willMove(toParent: nil)
       currentTab.view.removeFromSuperview()
-      currentTab.removeFromParentViewController()
+      currentTab.removeFromParent()
     }
 
     if let tabView = tab.view {
@@ -98,13 +94,9 @@ class AppBarManualTabsExample: UIViewController {
     }
 
     view.addSubview(tab.tableView)
-    view.sendSubview(toBack: tab.tableView)
+    view.sendSubviewToBack(tab.tableView)
 
-    #if swift(>=4.2)
     tab.didMove(toParent: self)
-    #else
-    tab.didMove(toParentViewController: self)
-    #endif
 
     tab.headerView = appBarViewController.headerView
 
@@ -127,7 +119,7 @@ class AppBarManualTabsExample: UIViewController {
   private func makeAppBar() -> MDCAppBarViewController {
     let appBarViewController = MDCAppBarViewController()
 
-    addChildViewController(appBarViewController)
+    addChild(appBarViewController)
 
     // Give the tab bar enough height to accomodate all possible item appearances.
     appBarViewController.headerView.minMaxHeightIncludesSafeArea = false
@@ -143,7 +135,7 @@ class AppBarManualTabsExample: UIViewController {
     return appBarViewController
   }
 
-  override var childViewControllerForStatusBarStyle: UIViewController? {
+  override var childForStatusBarStyle: UIViewController? {
     return appBarViewController
   }
 }
diff --git a/components/AppBar/examples/AppBarModalPresentationExample.swift b/components/AppBar/examples/AppBarModalPresentationExample.swift
index 7e9daa4305d..6f209d5b711 100644
--- a/components/AppBar/examples/AppBarModalPresentationExample.swift
+++ b/components/AppBar/examples/AppBarModalPresentationExample.swift
@@ -35,7 +35,7 @@ class AppBarModalPresentationSwiftExamplePresented: UITableViewController {
     appBarViewController.inferTopSafeAreaInsetFromViewController = true
     appBarViewController.headerView.minMaxHeightIncludesSafeArea = false
 
-    self.addChildViewController(appBarViewController)
+    self.addChild(appBarViewController)
     self.modalPresentationStyle = .formSheet
     self.modalTransitionStyle = .coverVertical
   }
@@ -55,11 +55,7 @@ class AppBarModalPresentationSwiftExamplePresented: UITableViewController {
     appBarViewController.headerView.trackingScrollView = self.tableView
 
     view.addSubview(appBarViewController.view)
-    #if swift(>=4.2)
     appBarViewController.didMove(toParent: self)
-    #else
-    appBarViewController.didMove(toParentViewController: self)
-    #endif
 
     self.navigationItem.rightBarButtonItem =
       UIBarButtonItem(title: "Touch", style: .done, target: nil, action: nil)
@@ -68,11 +64,11 @@ class AppBarModalPresentationSwiftExamplePresented: UITableViewController {
       UIBarButtonItem(title: "Dismiss", style: .done, target: self, action: #selector(dismissSelf))
   }
 
-  override var childViewControllerForStatusBarHidden: UIViewController? {
+  override var childForStatusBarHidden: UIViewController? {
     return appBarViewController
   }
 
-  override var childViewControllerForStatusBarStyle: UIViewController? {
+  override var childForStatusBarStyle: UIViewController? {
     return appBarViewController
   }
 
@@ -111,7 +107,7 @@ class AppBarModalPresentationSwiftExample: UITableViewController {
 
     self.title = "Modal Presentation (Swift)"
 
-    self.addChildViewController(appBarViewController)
+    self.addChild(appBarViewController)
   }
 
   required init?(coder aDecoder: NSCoder) {
@@ -127,21 +123,17 @@ class AppBarModalPresentationSwiftExample: UITableViewController {
     self.tableView.delegate = appBarViewController
 
     view.addSubview(appBarViewController.view)
-    #if swift(>=4.2)
     appBarViewController.didMove(toParent: self)
-    #else
-    appBarViewController.didMove(toParentViewController: self)
-    #endif
 
     self.navigationItem.rightBarButtonItem =
       UIBarButtonItem(title: "Detail", style: .done, target: self, action: #selector(presentModal))
   }
 
-  override var childViewControllerForStatusBarHidden: UIViewController? {
+  override var childForStatusBarHidden: UIViewController? {
     return appBarViewController
   }
 
-  override var childViewControllerForStatusBarStyle: UIViewController? {
+  override var childForStatusBarStyle: UIViewController? {
     return appBarViewController
   }
 
diff --git a/components/AppBar/examples/AppBarTypicalUseExample.swift b/components/AppBar/examples/AppBarTypicalUseExample.swift
index 6d0b37adef7..0658f0cce1f 100644
--- a/components/AppBar/examples/AppBarTypicalUseExample.swift
+++ b/components/AppBar/examples/AppBarTypicalUseExample.swift
@@ -39,7 +39,7 @@ class AppBarTypicalUseSwiftExample: UITableViewController {
     appBarViewController.headerView.minMaxHeightIncludesSafeArea = false
 
     // Step 2: Add the headerViewController as a child.
-    self.addChildViewController(appBarViewController)
+    self.addChild(appBarViewController)
   }
 
   required init?(coder aDecoder: NSCoder) {
@@ -60,11 +60,7 @@ class AppBarTypicalUseSwiftExample: UITableViewController {
 
     // Step 2: Register the App Bar views.
     view.addSubview(appBarViewController.view)
-    #if swift(>=4.2)
     appBarViewController.didMove(toParent: self)
-    #else
-    appBarViewController.didMove(toParentViewController: self)
-    #endif
 
     self.navigationItem.rightBarButtonItem =
       UIBarButtonItem(title: "Right", style: .done, target: nil, action: nil)
@@ -72,13 +68,13 @@ class AppBarTypicalUseSwiftExample: UITableViewController {
 
   // Optional step: If you allow the header view to hide the status bar you must implement this
   //                method and return the headerViewController.
-  override var childViewControllerForStatusBarHidden: UIViewController? {
+  override var childForStatusBarHidden: UIViewController? {
     return appBarViewController
   }
 
   // Optional step: The Header View Controller does basic inspection of the header view's background
   //                color to identify whether the status bar should be light or dark-themed.
-  override var childViewControllerForStatusBarStyle: UIViewController? {
+  override var childForStatusBarStyle: UIViewController? {
     return appBarViewController
   }
 
diff --git a/components/AppBar/examples/AppBarWithUITableViewController.swift b/components/AppBar/examples/AppBarWithUITableViewController.swift
index 2d3bea4ca76..9bb51ec2901 100644
--- a/components/AppBar/examples/AppBarWithUITableViewController.swift
+++ b/components/AppBar/examples/AppBarWithUITableViewController.swift
@@ -43,7 +43,7 @@ class AppBarWithUITableViewController: UITableViewController {
     commonInit()
   }
 
-  override init(style: UITableViewStyle) {
+  override init(style: UITableView.Style) {
     super.init(style: style)
     commonInit()
   }
@@ -54,7 +54,7 @@ class AppBarWithUITableViewController: UITableViewController {
     appBarViewController.inferTopSafeAreaInsetFromViewController = true
     appBarViewController.headerView.minMaxHeightIncludesSafeArea = false
 
-    self.addChildViewController(appBarViewController)
+    self.addChild(appBarViewController)
   }
 
   override func viewDidLoad() {
@@ -64,11 +64,7 @@ class AppBarWithUITableViewController: UITableViewController {
     appBarViewController.headerView.observesTrackingScrollViewScrollEvents = true
 
     view.addSubview(appBarViewController.view)
-    #if swift(>=4.2)
     appBarViewController.didMove(toParent: self)
-    #else
-    appBarViewController.didMove(toParentViewController: self)
-    #endif
 
     MDCAppBarColorThemer.applyColorScheme(colorScheme, to: appBarViewController)
     
diff --git a/components/AppBar/tests/unit/AppBarNavigationControllerTests.swift b/components/AppBar/tests/unit/AppBarNavigationControllerTests.swift
index 4aae008e37b..3c0eab8615b 100644
--- a/components/AppBar/tests/unit/AppBarNavigationControllerTests.swift
+++ b/components/AppBar/tests/unit/AppBarNavigationControllerTests.swift
@@ -48,7 +48,7 @@ class AppBarNavigationControllerTests: XCTestCase {
     let navigationController = MDCAppBarNavigationController(rootViewController: viewController)
 
     // Then
-    XCTAssertEqual(viewController.childViewControllers.count, 1,
+    XCTAssertEqual(viewController.children.count, 1,
                    "Expected there to be exactly one child view controller added to the view"
                     + " controller.")
 
@@ -56,12 +56,12 @@ class AppBarNavigationControllerTests: XCTestCase {
                    "The navigation controller's top view controller is supposed to be the pushed"
                     + " view controller, but it is \(viewController).")
 
-    XCTAssertTrue(viewController.childViewControllers.first is MDCFlexibleHeaderViewController,
+    XCTAssertTrue(viewController.children.first is MDCFlexibleHeaderViewController,
                   "The injected view controller is not a flexible header view controller, it is"
-                    + "\(String(describing: viewController.childViewControllers.first)) instead.")
+                    + "\(String(describing: viewController.children.first)) instead.")
 
     if let headerViewController
-      = viewController.childViewControllers.first as? MDCFlexibleHeaderViewController {
+      = viewController.children.first as? MDCFlexibleHeaderViewController {
       XCTAssertEqual(headerViewController.headerView.frame.height,
                      headerViewController.headerView.maximumHeight)
     }
@@ -75,7 +75,7 @@ class AppBarNavigationControllerTests: XCTestCase {
     navigationController.pushViewController(viewController, animated: false)
 
     // Then
-    XCTAssertEqual(viewController.childViewControllers.count, 1,
+    XCTAssertEqual(viewController.children.count, 1,
                    "Expected there to be exactly one child view controller added to the view"
                     + " controller.")
 
@@ -83,12 +83,12 @@ class AppBarNavigationControllerTests: XCTestCase {
                    "The navigation controller's top view controller is supposed to be the pushed"
                     + " view controller, but it is \(viewController).")
 
-    XCTAssertTrue(viewController.childViewControllers.first is MDCFlexibleHeaderViewController,
+    XCTAssertTrue(viewController.children.first is MDCFlexibleHeaderViewController,
                   "The injected view controller is not a flexible header view controller, it is"
-                    + "\(String(describing: viewController.childViewControllers.first)) instead.")
+                    + "\(String(describing: viewController.children.first)) instead.")
 
     if let headerViewController
-        = viewController.childViewControllers.first as? MDCFlexibleHeaderViewController {
+        = viewController.children.first as? MDCFlexibleHeaderViewController {
       XCTAssertEqual(headerViewController.headerView.frame.height,
                      headerViewController.headerView.maximumHeight)
     }
@@ -102,7 +102,7 @@ class AppBarNavigationControllerTests: XCTestCase {
     navigationController.viewControllers = [viewController]
 
     // Then
-    XCTAssertEqual(viewController.childViewControllers.count, 1,
+    XCTAssertEqual(viewController.children.count, 1,
                    "Expected there to be exactly one child view controller added to the view"
                     + " controller.")
 
@@ -110,12 +110,12 @@ class AppBarNavigationControllerTests: XCTestCase {
                    "The navigation controller's top view controller is supposed to be the pushed"
                     + " view controller, but it is \(viewController).")
 
-    XCTAssertTrue(viewController.childViewControllers.first is MDCFlexibleHeaderViewController,
+    XCTAssertTrue(viewController.children.first is MDCFlexibleHeaderViewController,
                   "The injected view controller is not a flexible header view controller, it is"
-                    + "\(String(describing: viewController.childViewControllers.first)) instead.")
+                    + "\(String(describing: viewController.children.first)) instead.")
 
     if let headerViewController
-      = viewController.childViewControllers.first as? MDCFlexibleHeaderViewController {
+      = viewController.children.first as? MDCFlexibleHeaderViewController {
       XCTAssertEqual(headerViewController.headerView.frame.height,
                      headerViewController.headerView.maximumHeight)
     }
@@ -129,7 +129,7 @@ class AppBarNavigationControllerTests: XCTestCase {
     navigationController.setViewControllers([viewController], animated: false)
 
     // Then
-    XCTAssertEqual(viewController.childViewControllers.count, 1,
+    XCTAssertEqual(viewController.children.count, 1,
                    "Expected there to be exactly one child view controller added to the view"
                     + " controller.")
 
@@ -137,12 +137,12 @@ class AppBarNavigationControllerTests: XCTestCase {
                    "The navigation controller's top view controller is supposed to be the pushed"
                     + " view controller, but it is \(viewController).")
 
-    XCTAssertTrue(viewController.childViewControllers.first is MDCFlexibleHeaderViewController,
+    XCTAssertTrue(viewController.children.first is MDCFlexibleHeaderViewController,
                   "The injected view controller is not a flexible header view controller, it is"
-                    + "\(String(describing: viewController.childViewControllers.first)) instead.")
+                    + "\(String(describing: viewController.children.first)) instead.")
 
     if let headerViewController
-      = viewController.childViewControllers.first as? MDCFlexibleHeaderViewController {
+      = viewController.children.first as? MDCFlexibleHeaderViewController {
       XCTAssertEqual(headerViewController.headerView.frame.height,
                      headerViewController.headerView.maximumHeight)
     }
@@ -157,7 +157,7 @@ class AppBarNavigationControllerTests: XCTestCase {
     navigationController.pushViewController(container, animated: false)
 
     // Then
-    XCTAssertEqual(container.childViewControllers.count, 2,
+    XCTAssertEqual(container.children.count, 2,
                    "An App Bar container view controller should have exactly two child view"
                     + " controllers. A failure of this assertion implies that the navigation"
                     + " controller may have injected another App Bar.")
@@ -168,19 +168,15 @@ class AppBarNavigationControllerTests: XCTestCase {
     let viewController = UIViewController()
     let container = MDCAppBarContainerViewController(contentViewController: viewController)
     let nestedContainer = UIViewController()
-    nestedContainer.addChildViewController(container)
+    nestedContainer.addChild(container)
     nestedContainer.view.addSubview(container.view)
-    #if swift(>=4.2)
     container.didMove(toParent: nestedContainer)
-    #else
-    container.didMove(toParentViewController: nestedContainer)
-    #endif
 
     // When
     navigationController.pushViewController(nestedContainer, animated: false)
 
     // Then
-    XCTAssertEqual(nestedContainer.childViewControllers.count, 1,
+    XCTAssertEqual(nestedContainer.children.count, 1,
                    "The view controller hierarchy already has one app bar view controller, but it"
                     + " appears to have possibly added another.")
   }
@@ -189,19 +185,15 @@ class AppBarNavigationControllerTests: XCTestCase {
     // Given
     let viewController = UIViewController()
     let fhvc = MDCFlexibleHeaderViewController()
-    viewController.addChildViewController(fhvc)
+    viewController.addChild(fhvc)
     viewController.view.addSubview(fhvc.view)
-    #if swift(>=4.2)
     fhvc.didMove(toParent: viewController)
-    #else
-    fhvc.didMove(toParentViewController: viewController)
-    #endif
 
     // When
     navigationController.pushViewController(viewController, animated: false)
 
     // Then
-    XCTAssertEqual(viewController.childViewControllers.count, 1,
+    XCTAssertEqual(viewController.children.count, 1,
                    "The navigation controller may have injected another App Bar when it shouldn't"
                     + " have.")
   }
@@ -219,7 +211,7 @@ class AppBarNavigationControllerTests: XCTestCase {
     XCTAssertNotNil(appBar, "Could not retrieve the injected App Bar.")
 
     if let appBar = appBar {
-      XCTAssertEqual(navigationController.childViewControllerForStatusBarStyle,
+      XCTAssertEqual(navigationController.childForStatusBarStyle,
                      appBar.headerViewController,
                      "The navigation controller should be using the injected app bar's flexible"
                       + "header view controller for status bar style updates.")
diff --git a/components/AppBar/tests/unit/AppBarTypographyThemerTests.swift b/components/AppBar/tests/unit/AppBarTypographyThemerTests.swift
index dfcfad03108..44058ae65bb 100644
--- a/components/AppBar/tests/unit/AppBarTypographyThemerTests.swift
+++ b/components/AppBar/tests/unit/AppBarTypographyThemerTests.swift
@@ -20,8 +20,8 @@ import MaterialComponents.MaterialTypography
 class AppBarTypographyThemerTests: XCTestCase {
 
   func traitsForFont(_ font: UIFont) -> [String: NSNumber] {
-    guard let fontTraits =
-          font.fontDescriptor.object(forKey: UIFontDescriptorTraitsAttribute) as? [String: NSNumber]
+    guard let fontTraits = font.fontDescriptor.object(forKey: UIFontDescriptor.AttributeName.traits)
+      as? [String: NSNumber]
       else {
         return [:]
     }
diff --git a/components/AppBar/tests/unit/AppBarWrappingLegacyTopLayoutGuideTests.swift b/components/AppBar/tests/unit/AppBarWrappingLegacyTopLayoutGuideTests.swift
index 30132fc7f86..10ae81cf1ab 100644
--- a/components/AppBar/tests/unit/AppBarWrappingLegacyTopLayoutGuideTests.swift
+++ b/components/AppBar/tests/unit/AppBarWrappingLegacyTopLayoutGuideTests.swift
@@ -34,11 +34,9 @@ class AppBarWrappingLegacyTopLayoutGuideTests: XCTestCase {
     // Then
     XCTAssertNil(container.appBar.headerViewController.topLayoutGuideViewController)
     XCTAssertEqual(contentViewController.topLayoutGuide.length, 0)
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       XCTAssertEqual(contentViewController.additionalSafeAreaInsets.top, 0)
     }
-    #endif
   }
 
   // MARK: Untracked table view
@@ -57,12 +55,10 @@ class AppBarWrappingLegacyTopLayoutGuideTests: XCTestCase {
     // Then
     XCTAssertNil(container.appBar.headerViewController.topLayoutGuideViewController)
     XCTAssertEqual(contentViewController.topLayoutGuide.length, 0)
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       XCTAssertEqual(contentViewController.additionalSafeAreaInsets.top, 0)
       XCTAssertEqual(contentViewController.tableView.adjustedContentInset.top, 0)
     }
-    #endif
   }
 
   // MARK: Tracked table view
@@ -84,14 +80,12 @@ class AppBarWrappingLegacyTopLayoutGuideTests: XCTestCase {
     // Then
     XCTAssertNil(container.appBar.headerViewController.topLayoutGuideViewController)
     XCTAssertEqual(contentViewController.topLayoutGuide.length, 0)
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       XCTAssertEqual(contentViewController.additionalSafeAreaInsets.top, 0)
       XCTAssertEqual(contentViewController.tableView.adjustedContentInset.top,
                      container.appBar.headerViewController.headerView.maximumHeight
                       + MDCDeviceTopSafeAreaInset())
     }
-    #endif
   }
 
   // MARK: Untracked collection view
@@ -111,12 +105,10 @@ class AppBarWrappingLegacyTopLayoutGuideTests: XCTestCase {
     // Then
     XCTAssertNil(container.appBar.headerViewController.topLayoutGuideViewController)
     XCTAssertEqual(contentViewController.topLayoutGuide.length, 0)
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       XCTAssertEqual(contentViewController.additionalSafeAreaInsets.top, 0)
       XCTAssertEqual(contentViewController.collectionView!.adjustedContentInset.top, 0)
     }
-    #endif
   }
 
   // MARK: Tracked collection view
@@ -140,14 +132,12 @@ class AppBarWrappingLegacyTopLayoutGuideTests: XCTestCase {
     // Then
     XCTAssertNil(container.appBar.headerViewController.topLayoutGuideViewController)
     XCTAssertEqual(contentViewController.topLayoutGuide.length, 0)
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       XCTAssertEqual(contentViewController.additionalSafeAreaInsets.top, 0)
       XCTAssertEqual(contentViewController.collectionView!.adjustedContentInset.top,
                      container.appBar.headerViewController.headerView.maximumHeight
                       + MDCDeviceTopSafeAreaInset())
     }
-    #endif
   }
 
 }
diff --git a/components/AppBar/tests/unit/AppBarWrappingTopLayoutGuideTests.swift b/components/AppBar/tests/unit/AppBarWrappingTopLayoutGuideTests.swift
index 971bb82e8d3..42e41dfd5d8 100644
--- a/components/AppBar/tests/unit/AppBarWrappingTopLayoutGuideTests.swift
+++ b/components/AppBar/tests/unit/AppBarWrappingTopLayoutGuideTests.swift
@@ -36,13 +36,11 @@ class AppBarWrappingTopLayoutGuideTests: XCTestCase {
     XCTAssertEqual(contentViewController.view.frame, container.view.bounds)
     XCTAssertEqual(contentViewController.topLayoutGuide.length,
                    container.appBar.headerViewController.headerView.frame.maxY)
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       XCTAssertEqual(contentViewController.additionalSafeAreaInsets.top,
                      container.appBar.headerViewController.headerView.frame.maxY
                       - MDCDeviceTopSafeAreaInset())
     }
-    #endif
   }
 
   func testEarlyViewLoadStillAffectsTopLayoutGuide() {
@@ -61,13 +59,11 @@ class AppBarWrappingTopLayoutGuideTests: XCTestCase {
     XCTAssertEqual(contentViewController.view.frame, container.view.bounds)
     XCTAssertEqual(contentViewController.topLayoutGuide.length,
                    container.appBar.headerViewController.headerView.frame.maxY)
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       XCTAssertEqual(contentViewController.additionalSafeAreaInsets.top,
                      container.appBar.headerViewController.headerView.frame.maxY
                       - MDCDeviceTopSafeAreaInset())
     }
-    #endif
   }
 
   // MARK: Untracked table view
@@ -88,14 +84,12 @@ class AppBarWrappingTopLayoutGuideTests: XCTestCase {
     XCTAssertEqual(contentViewController.view.frame, container.view.bounds)
     XCTAssertEqual(contentViewController.topLayoutGuide.length,
                    container.appBar.headerViewController.headerView.frame.maxY)
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       XCTAssertEqual(contentViewController.additionalSafeAreaInsets.top,
                      container.appBar.headerViewController.headerView.frame.maxY
                       - MDCDeviceTopSafeAreaInset())
       XCTAssertEqual(contentViewController.tableView.adjustedContentInset.top, 0)
     }
-    #endif
   }
 
   // MARK: Tracked table view
@@ -119,13 +113,11 @@ class AppBarWrappingTopLayoutGuideTests: XCTestCase {
     // Then
     XCTAssertEqual(contentViewController.topLayoutGuide.length,
                    container.appBar.headerViewController.headerView.frame.maxY)
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       XCTAssertEqual(contentViewController.additionalSafeAreaInsets.top, 0)
       XCTAssertEqual(contentViewController.tableView.adjustedContentInset.top,
                      container.appBar.headerViewController.headerView.maximumHeight)
     }
-    #endif
   }
 
   // MARK: Untracked collection view
@@ -148,14 +140,12 @@ class AppBarWrappingTopLayoutGuideTests: XCTestCase {
     XCTAssertEqual(contentViewController.view.frame, container.view.bounds)
     XCTAssertEqual(contentViewController.topLayoutGuide.length,
                    container.appBar.headerViewController.headerView.frame.maxY)
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       XCTAssertEqual(contentViewController.additionalSafeAreaInsets.top,
                      container.appBar.headerViewController.headerView.frame.maxY
                       - MDCDeviceTopSafeAreaInset())
       XCTAssertEqual(contentViewController.collectionView!.adjustedContentInset.top, 0)
     }
-    #endif
   }
 
   // MARK: Tracked collection view view
@@ -182,13 +172,11 @@ class AppBarWrappingTopLayoutGuideTests: XCTestCase {
     XCTAssertEqual(contentViewController.view.frame, container.view.bounds)
     XCTAssertEqual(contentViewController.topLayoutGuide.length,
                    container.appBar.headerViewController.headerView.frame.maxY)
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       XCTAssertEqual(contentViewController.additionalSafeAreaInsets.top, 0)
       XCTAssertEqual(contentViewController.collectionView!.adjustedContentInset.top,
                      container.appBar.headerViewController.headerView.maximumHeight)
     }
-    #endif
   }
 
 }
diff --git a/components/BottomAppBar/examples/BottomAppBarTypicalUseExample.swift b/components/BottomAppBar/examples/BottomAppBarTypicalUseExample.swift
index 1f6be75a862..43a76494495 100644
--- a/components/BottomAppBar/examples/BottomAppBarTypicalUseExample.swift
+++ b/components/BottomAppBar/examples/BottomAppBarTypicalUseExample.swift
@@ -34,12 +34,13 @@ class BottomAppBarTypicalUseSwiftExample: UIViewController {
     super.init(nibName: nil, bundle: nil)
 
     self.title = "Bottom App Bar (Swift)"
-    self.addChildViewController(appBarViewController)
+    self.addChild(appBarViewController)
 
     let color = UIColor(white: 0.2, alpha:1)
     appBarViewController.headerView.backgroundColor = color
     appBarViewController.navigationBar.tintColor = .white
-    appBarViewController.navigationBar.titleTextAttributes = [NSForegroundColorAttributeName : UIColor.white]
+    appBarViewController.navigationBar.titleTextAttributes =
+      [NSAttributedString.Key.foregroundColor : UIColor.white]
     commonInitBottomAppBarTypicalUseSwiftExample()
   }
 
@@ -52,11 +53,7 @@ class BottomAppBarTypicalUseSwiftExample: UIViewController {
     super.viewDidLoad()
 
     view.addSubview(appBarViewController.view)
-    #if swift(>=4.2)
     appBarViewController.didMove(toParent: self)
-    #else
-    appBarViewController.didMove(toParentViewController: self)
-    #endif
   }
 
   func commonInitBottomAppBarTypicalUseSwiftExample() {
@@ -133,14 +130,11 @@ class BottomAppBarTypicalUseSwiftExample: UIViewController {
     layoutBottomAppBar()
   }
 
-  #if swift(>=3.2)
   @available(iOS 11, *)
   override func viewSafeAreaInsetsDidChange() {
     super.viewSafeAreaInsetsDidChange()
     layoutBottomAppBar()
   }
-  #endif
-
 }
 
 // MARK: Catalog by convention
diff --git a/components/BottomNavigation/BUILD b/components/BottomNavigation/BUILD
index 1739b88d612..94f9ae925ff 100644
--- a/components/BottomNavigation/BUILD
+++ b/components/BottomNavigation/BUILD
@@ -147,7 +147,7 @@ swift_library(
     ),
     copts = [
         "-swift-version",
-        "3",
+        "4.2",
     ],
     deps = [
         ":BottomNavigationBeta",
diff --git a/components/BottomNavigation/examples/BottomNavigationExplicitlySetColorExample.swift b/components/BottomNavigation/examples/BottomNavigationExplicitlySetColorExample.swift
index 41c1cd742d8..205df7d5453 100644
--- a/components/BottomNavigation/examples/BottomNavigationExplicitlySetColorExample.swift
+++ b/components/BottomNavigation/examples/BottomNavigationExplicitlySetColorExample.swift
@@ -61,13 +61,11 @@ class BottomNavigationExplicitlySetColorExample: UIViewController {
     layoutBottomNavBar()
   }
 
-  #if swift(>=3.2)
   @available(iOS 11, *)
   override func viewSafeAreaInsetsDidChange() {
     super.viewSafeAreaInsetsDidChange()
     layoutBottomNavBar()
   }
-  #endif
 
   override func viewDidLoad() {
     super.viewDidLoad()
diff --git a/components/BottomNavigation/examples/BottomNavigationNilBadges.swift b/components/BottomNavigation/examples/BottomNavigationNilBadges.swift
index f0154bd52fc..6a8dfcddf07 100644
--- a/components/BottomNavigation/examples/BottomNavigationNilBadges.swift
+++ b/components/BottomNavigation/examples/BottomNavigationNilBadges.swift
@@ -82,13 +82,11 @@ class BottomNavigationNilBadges : UIViewController {
     layoutBottomNavBar()
   }
 
-  #if swift(>=3.2)
   @available(iOS 11, *)
   override func viewSafeAreaInsetsDidChange() {
     super.viewSafeAreaInsetsDidChange()
     layoutBottomNavBar()
   }
-  #endif
 
   override func viewWillAppear(_ animated: Bool) {
     super.viewWillAppear(animated)
diff --git a/components/BottomNavigation/examples/BottomNavigationResetButtons.swift b/components/BottomNavigation/examples/BottomNavigationResetButtons.swift
index 72fa00e7c53..02ba7707913 100644
--- a/components/BottomNavigation/examples/BottomNavigationResetButtons.swift
+++ b/components/BottomNavigation/examples/BottomNavigationResetButtons.swift
@@ -74,13 +74,11 @@ class BottomNavigationResetExample: UIViewController {
     layoutBottomNavBar()
   }
 
-  #if swift(>=3.2)
   @available(iOS 11, *)
   override func viewSafeAreaInsetsDidChange() {
     super.viewSafeAreaInsetsDidChange()
     layoutBottomNavBar()
   }
-  #endif
 
   override func viewDidLoad() {
     super.viewDidLoad()
diff --git a/components/BottomNavigation/examples/BottomNavigationSelectedIconExample.swift b/components/BottomNavigation/examples/BottomNavigationSelectedIconExample.swift
index 2ef25607650..1128705b17e 100644
--- a/components/BottomNavigation/examples/BottomNavigationSelectedIconExample.swift
+++ b/components/BottomNavigation/examples/BottomNavigationSelectedIconExample.swift
@@ -61,13 +61,11 @@ class BottomNavigationSelectedIconExample: UIViewController {
     layoutBottomNavBar()
   }
 
-  #if swift(>=3.2)
   @available(iOS 11, *)
   override func viewSafeAreaInsetsDidChange() {
     super.viewSafeAreaInsetsDidChange()
     layoutBottomNavBar()
   }
-  #endif
 }
 
 
diff --git a/components/BottomNavigation/examples/BottomNavigationTitleVisibilityChangeExample.swift b/components/BottomNavigation/examples/BottomNavigationTitleVisibilityChangeExample.swift
index 53b748931d7..e1b8c402f06 100644
--- a/components/BottomNavigation/examples/BottomNavigationTitleVisibilityChangeExample.swift
+++ b/components/BottomNavigation/examples/BottomNavigationTitleVisibilityChangeExample.swift
@@ -87,7 +87,7 @@ class BottomNavigationTitleVisibilityChangeExample: UIViewController, MDCBottomN
 
     var viewBounds = view.bounds;
     if #available(iOS 11.0, *) {
-      viewBounds = UIEdgeInsetsInsetRect(viewBounds, view.safeAreaInsets)
+      viewBounds = viewBounds.inset(by: view.safeAreaInsets)
     }
     let labelWidth = min(viewBounds.size.width - 32, 480);
     let labelSize = instructionLabel.sizeThatFits(CGSize(width: labelWidth,
diff --git a/components/BottomSheet/BUILD b/components/BottomSheet/BUILD
index 4cf949f0a5c..dce0bacb462 100644
--- a/components/BottomSheet/BUILD
+++ b/components/BottomSheet/BUILD
@@ -109,7 +109,7 @@ swift_library(
     srcs = glob(["tests/unit/*.swift"]),
     copts = [
         "-swift-version",
-        "3",
+        "4.2",
     ],
     visibility = ["//visibility:private"],
     deps = [
diff --git a/components/ButtonBar/BUILD b/components/ButtonBar/BUILD
index f215882cc39..77bec95f5e0 100644
--- a/components/ButtonBar/BUILD
+++ b/components/ButtonBar/BUILD
@@ -122,7 +122,7 @@ swift_library(
     ]),
     copts = [
         "-swift-version",
-        "3",
+        "4.2",
     ],
     visibility = ["//visibility:private"],
     deps = [
diff --git a/components/ButtonBar/examples/ButtonBarTypicalUseExample.swift b/components/ButtonBar/examples/ButtonBarTypicalUseExample.swift
index 4078c123c5f..5882f169cd8 100644
--- a/components/ButtonBar/examples/ButtonBarTypicalUseExample.swift
+++ b/components/ButtonBar/examples/ButtonBarTypicalUseExample.swift
@@ -35,7 +35,7 @@ class ButtonBarTypicalUseSwiftExample: UIViewController {
     buttonBar.applyPrimaryTheme(withScheme: scheme)
 
     // MDCButtonBar ignores the style of UIBarButtonItem.
-    let ignored: UIBarButtonItemStyle = .done
+    let ignored: UIBarButtonItem.Style = .done
 
     let actionItem = UIBarButtonItem(
       title: "Action",
diff --git a/components/ButtonBar/tests/unit/ButtonBarIssue370Tests.swift b/components/ButtonBar/tests/unit/ButtonBarIssue370Tests.swift
index d3b21c1eb97..ec4c9699447 100644
--- a/components/ButtonBar/tests/unit/ButtonBarIssue370Tests.swift
+++ b/components/ButtonBar/tests/unit/ButtonBarIssue370Tests.swift
@@ -23,21 +23,21 @@ import MaterialComponents.MaterialButtons
 class ButtonBarIssue370Tests: XCTestCase {
 
   var buttonBar: MDCButtonBar!
-  let globalAttributes = [NSForegroundColorAttributeName: UIColor.blue]
-  let directAttributes = [NSForegroundColorAttributeName: UIColor.blue]
-  let fontAttributes = [NSFontAttributeName: UIFont.systemFont(ofSize: 12)]
+  let globalAttributes = [NSAttributedString.Key.foregroundColor: UIColor.blue]
+  let directAttributes = [NSAttributedString.Key.foregroundColor: UIColor.blue]
+  let fontAttributes = [NSAttributedString.Key.font: UIFont.systemFont(ofSize: 12)]
 
   override func setUp() {
     buttonBar = MDCButtonBar()
   }
 
   override func tearDown() {
-    UIBarButtonItem.appearance().setTitleTextAttributes(nil, for: UIControlState())
+    UIBarButtonItem.appearance().setTitleTextAttributes(nil, for: UIControl.State())
   }
 
   func testDirectOnly() {
     let item = UIBarButtonItem(title: "Text", style: .plain, target: nil, action: nil)
-    item.setTitleTextAttributes(directAttributes, for: UIControlState())
+    item.setTitleTextAttributes(directAttributes, for: UIControl.State())
     buttonBar.items = [item]
 
     forEachButton { button in
@@ -47,9 +47,9 @@ class ButtonBarIssue370Tests: XCTestCase {
   }
 
   func testGlobalAppearanceOnly() {
-    UIBarButtonItem.appearance().setTitleTextAttributes(globalAttributes, for: UIControlState())
+    UIBarButtonItem.appearance().setTitleTextAttributes(globalAttributes, for: UIControl.State())
 
-    if UIBarButtonItem.appearance().titleTextAttributes(for: UIControlState()) == nil {
+    if UIBarButtonItem.appearance().titleTextAttributes(for: UIControl.State()) == nil {
       // This feature is not supported on this OS
       return
     }
@@ -64,12 +64,12 @@ class ButtonBarIssue370Tests: XCTestCase {
   }
 
   func testGlobalAppearanceAndDirectOverwriting() {
-    UIBarButtonItem.appearance().setTitleTextAttributes(globalAttributes, for: UIControlState())
+    UIBarButtonItem.appearance().setTitleTextAttributes(globalAttributes, for: UIControl.State())
 
     let item = UIBarButtonItem(title: "Text", style: .plain, target: nil, action: nil)
 
     // Should take priority.
-    item.setTitleTextAttributes(directAttributes, for: UIControlState())
+    item.setTitleTextAttributes(directAttributes, for: UIControl.State())
 
     buttonBar.items = [item]
 
@@ -80,18 +80,18 @@ class ButtonBarIssue370Tests: XCTestCase {
   }
 
   func testGlobalAppearanceAndDirectMerging() {
-    UIBarButtonItem.appearance().setTitleTextAttributes(fontAttributes, for: UIControlState())
+    UIBarButtonItem.appearance().setTitleTextAttributes(fontAttributes, for: UIControl.State())
 
-    if UIBarButtonItem.appearance().titleTextAttributes(for: UIControlState()) == nil {
+    if UIBarButtonItem.appearance().titleTextAttributes(for: UIControl.State()) == nil {
       // This feature is not supported on this OS
       return
     }
 
     let item = UIBarButtonItem(title: "Text", style: .plain, target: nil, action: nil)
-    item.setTitleTextAttributes(directAttributes, for: UIControlState())
+    item.setTitleTextAttributes(directAttributes, for: UIControl.State())
     buttonBar.items = [item]
 
-    var composite: [String: Any] = fontAttributes
+    var composite: [NSAttributedString.Key: Any] = fontAttributes
     for (key, value) in directAttributes {
       composite[key] = value
     }
diff --git a/components/ButtonBar/tests/unit/ButtonBarIssue516Tests.swift b/components/ButtonBar/tests/unit/ButtonBarIssue516Tests.swift
index b3d8819a458..7aa44924bf6 100644
--- a/components/ButtonBar/tests/unit/ButtonBarIssue516Tests.swift
+++ b/components/ButtonBar/tests/unit/ButtonBarIssue516Tests.swift
@@ -42,8 +42,8 @@ class ButtonBarIssue516Tests: XCTestCase {
     buttons = buttons.sorted { (button1, button2) -> Bool in
       return button1.frame.origin.x < button2.frame.origin.x
     }
-    XCTAssertEqual((buttons[0] as! MDCButton).title(for: UIControlState()), "LEFT")
-    XCTAssertEqual((buttons[1] as! MDCButton).title(for: UIControlState()), "RIGHT")
+    XCTAssertEqual((buttons[0] as! MDCButton).title(for: UIControl.State()), "LEFT")
+    XCTAssertEqual((buttons[1] as! MDCButton).title(for: UIControl.State()), "RIGHT")
   }
 
   func testLayoutPositionLeading() {
@@ -59,8 +59,8 @@ class ButtonBarIssue516Tests: XCTestCase {
     buttons = buttons.sorted { (button1, button2) -> Bool in
       return button1.frame.origin.x < button2.frame.origin.x
     }
-    XCTAssertEqual((buttons[0] as! MDCButton).title(for: UIControlState()), "LEFT")
-    XCTAssertEqual((buttons[1] as! MDCButton).title(for: UIControlState()), "RIGHT")
+    XCTAssertEqual((buttons[0] as! MDCButton).title(for: UIControl.State()), "LEFT")
+    XCTAssertEqual((buttons[1] as! MDCButton).title(for: UIControl.State()), "RIGHT")
   }
 
   func testLayoutPositionTrailing() {
@@ -76,7 +76,7 @@ class ButtonBarIssue516Tests: XCTestCase {
     buttons = buttons.sorted { (button1, button2) -> Bool in
       return button1.frame.origin.x < button2.frame.origin.x
     }
-    XCTAssertEqual((buttons[0] as! MDCButton).title(for: UIControlState()), "RIGHT")
-    XCTAssertEqual((buttons[1] as! MDCButton).title(for: UIControlState()), "LEFT")
+    XCTAssertEqual((buttons[0] as! MDCButton).title(for: UIControl.State()), "RIGHT")
+    XCTAssertEqual((buttons[1] as! MDCButton).title(for: UIControl.State()), "LEFT")
   }
 }
diff --git a/components/ButtonBar/tests/unit/ButtonBarObservationTests.swift b/components/ButtonBar/tests/unit/ButtonBarObservationTests.swift
index 972905927a0..98d154dc604 100644
--- a/components/ButtonBar/tests/unit/ButtonBarObservationTests.swift
+++ b/components/ButtonBar/tests/unit/ButtonBarObservationTests.swift
@@ -45,7 +45,7 @@ class ButtonBarObservationTests: XCTestCase {
     buttonBar.layoutSubviews()
 
     // Then
-    let titles = buttonBar.subviews.flatMap { $0 as? MDCButton }.flatMap { $0.title(for: .normal) }
+    let titles = buttonBar.subviews.compactMap { $0 as? MDCButton }.compactMap { $0.title(for: .normal) }
     XCTAssertEqual(titles, [item.title!])
   }
 
@@ -60,7 +60,7 @@ class ButtonBarObservationTests: XCTestCase {
 
     // Then
     let images =
-        buttonBar.subviews.flatMap { $0 as? MDCButton }.flatMap { $0.image(for: .normal) }
+        buttonBar.subviews.compactMap { $0 as? MDCButton }.compactMap { $0.image(for: .normal) }
     XCTAssertEqual(images, [item.image!])
   }
 
@@ -81,22 +81,22 @@ class ButtonBarObservationTests: XCTestCase {
 
     // Then
     let accessibilityHints =
-        buttonBar.subviews.flatMap { $0 as? MDCButton }.flatMap { $0.accessibilityHint }
+        buttonBar.subviews.compactMap { $0 as? MDCButton }.compactMap { $0.accessibilityHint }
     XCTAssertEqual(accessibilityHints, [item.accessibilityHint!])
     let accessibilityIdentifiers =
-        buttonBar.subviews.flatMap { $0 as? MDCButton }.flatMap { $0.accessibilityIdentifier }
+        buttonBar.subviews.compactMap { $0 as? MDCButton }.compactMap { $0.accessibilityIdentifier }
     XCTAssertEqual(accessibilityIdentifiers, [item.accessibilityIdentifier!])
     let accessibilityLabels =
-        buttonBar.subviews.flatMap { $0 as? MDCButton }.flatMap { $0.accessibilityLabel }
+        buttonBar.subviews.compactMap { $0 as? MDCButton }.compactMap { $0.accessibilityLabel }
     XCTAssertEqual(accessibilityLabels, [item.accessibilityLabel!])
     let accessibilityValues =
-        buttonBar.subviews.flatMap { $0 as? MDCButton }.flatMap { $0.accessibilityValue }
+        buttonBar.subviews.compactMap { $0 as? MDCButton }.compactMap { $0.accessibilityValue }
     XCTAssertEqual(accessibilityValues, [item.accessibilityValue!])
-    let enabled = buttonBar.subviews.flatMap { $0 as? MDCButton }.map { $0.isEnabled }
+    let enabled = buttonBar.subviews.compactMap { $0 as? MDCButton }.map { $0.isEnabled }
     XCTAssertEqual(enabled, [item.isEnabled])
-    let tags = buttonBar.subviews.flatMap { $0 as? MDCButton }.map { $0.tag }
+    let tags = buttonBar.subviews.compactMap { $0 as? MDCButton }.map { $0.tag }
     XCTAssertEqual(tags, [item.tag])
-    let tintColors = buttonBar.subviews.flatMap { $0 as? MDCButton }.flatMap { $0.tintColor }
+    let tintColors = buttonBar.subviews.compactMap { $0 as? MDCButton }.compactMap { $0.tintColor }
     XCTAssertEqual(tintColors, [item.tintColor!])
   }
 
@@ -114,7 +114,7 @@ class ButtonBarObservationTests: XCTestCase {
 
     // Then
     let accessibilityLabels =
-        buttonBar.subviews.flatMap { $0 as? MDCButton }.flatMap { $0.accessibilityHint }
+        buttonBar.subviews.compactMap { $0 as? MDCButton }.compactMap { $0.accessibilityHint }
     XCTAssertEqual(accessibilityLabels, [item.accessibilityHint!])
   }
 
@@ -130,7 +130,7 @@ class ButtonBarObservationTests: XCTestCase {
 
     // Then
     let accessibilityIdentifiers =
-        buttonBar.subviews.flatMap { $0 as? MDCButton }.flatMap { $0.accessibilityIdentifier }
+        buttonBar.subviews.compactMap { $0 as? MDCButton }.compactMap { $0.accessibilityIdentifier }
     XCTAssertEqual(accessibilityIdentifiers, [item.accessibilityIdentifier!])
   }
 
@@ -146,7 +146,7 @@ class ButtonBarObservationTests: XCTestCase {
 
     // Then
     let accessibilityLabels =
-        buttonBar.subviews.flatMap { $0 as? MDCButton }.flatMap { $0.accessibilityLabel }
+        buttonBar.subviews.compactMap { $0 as? MDCButton }.compactMap { $0.accessibilityLabel }
     XCTAssertEqual(accessibilityLabels, [item.accessibilityLabel!])
   }
 
@@ -162,7 +162,7 @@ class ButtonBarObservationTests: XCTestCase {
 
     // Then
     let accessibilityValues =
-        buttonBar.subviews.flatMap { $0 as? MDCButton }.flatMap { $0.accessibilityValue }
+        buttonBar.subviews.compactMap { $0 as? MDCButton }.compactMap { $0.accessibilityValue }
     XCTAssertEqual(accessibilityValues, [item.accessibilityValue!])
   }
 
@@ -177,7 +177,7 @@ class ButtonBarObservationTests: XCTestCase {
     item.isEnabled = false
 
     // Then
-    let enabled = buttonBar.subviews.flatMap { $0 as? MDCButton }.map { $0.isEnabled }
+    let enabled = buttonBar.subviews.compactMap { $0 as? MDCButton }.map { $0.isEnabled }
     XCTAssertEqual(enabled, [item.isEnabled])
   }
 
@@ -193,7 +193,7 @@ class ButtonBarObservationTests: XCTestCase {
 
     // Then
     let images =
-      buttonBar.subviews.flatMap { $0 as? MDCButton }.flatMap { $0.image(for: .normal) }
+      buttonBar.subviews.compactMap { $0 as? MDCButton }.compactMap { $0.image(for: .normal) }
     XCTAssertEqual(images, [item.image!])
   }
 
@@ -208,7 +208,7 @@ class ButtonBarObservationTests: XCTestCase {
     item.tag = 50
 
     // Then
-    let tags = buttonBar.subviews.flatMap { $0 as? MDCButton }.map { $0.tag }
+    let tags = buttonBar.subviews.compactMap { $0 as? MDCButton }.map { $0.tag }
     XCTAssertEqual(tags, [item.tag])
   }
 
@@ -223,14 +223,14 @@ class ButtonBarObservationTests: XCTestCase {
     item.tintColor = .red
 
     // Then
-    let tintColors = buttonBar.subviews.flatMap { $0 as? MDCButton }.flatMap { $0.tintColor }
+    let tintColors = buttonBar.subviews.compactMap { $0 as? MDCButton }.compactMap { $0.tintColor }
     XCTAssertEqual(tintColors, [item.tintColor!])
 
     // Verify that the tint color reverts to the default
     item.tintColor = nil
 
     do {
-      let tintColors = buttonBar.subviews.flatMap { $0 as? MDCButton }.flatMap { $0.tintColor }
+      let tintColors = buttonBar.subviews.compactMap { $0 as? MDCButton }.compactMap { $0.tintColor }
       XCTAssertEqual(tintColors, [buttonBar.tintColor])
     }
   }
@@ -246,7 +246,7 @@ class ButtonBarObservationTests: XCTestCase {
     item.tintColor = nil
 
     // Then
-    let tintColors = buttonBar.subviews.flatMap { $0 as? MDCButton }.flatMap { $0.tintColor }
+    let tintColors = buttonBar.subviews.compactMap { $0 as? MDCButton }.compactMap { $0.tintColor }
     XCTAssertEqual(tintColors, [buttonBar.tintColor])
   }
 
@@ -260,7 +260,7 @@ class ButtonBarObservationTests: XCTestCase {
     item.title = "NEW TITLE"
 
     // Then
-    let titles = buttonBar.subviews.flatMap { $0 as? MDCButton }.flatMap { $0.title(for: .normal) }
+    let titles = buttonBar.subviews.compactMap { $0 as? MDCButton }.compactMap { $0.title(for: .normal) }
     XCTAssertEqual(titles, [item.title!])
   }
 
diff --git a/components/Buttons/BUILD b/components/Buttons/BUILD
index 2af2563f89f..6edb311ce86 100644
--- a/components/Buttons/BUILD
+++ b/components/Buttons/BUILD
@@ -181,7 +181,7 @@ swift_library(
     ]),
     copts = [
         "-swift-version",
-        "3",
+        "4.2",
     ],
     visibility = ["//visibility:private"],
     deps = [
diff --git a/components/Buttons/examples/ButtonsCustomFontViewController.swift b/components/Buttons/examples/ButtonsCustomFontViewController.swift
index f25f746836e..b948c759a23 100644
--- a/components/Buttons/examples/ButtonsCustomFontViewController.swift
+++ b/components/Buttons/examples/ButtonsCustomFontViewController.swift
@@ -43,7 +43,7 @@ class ButtonsCustomFontViewController: UIViewController {
     view.backgroundColor = containerScheme.colorScheme.backgroundColor
     let flatButtonStatic = MDCButton()
     flatButtonStatic.applyContainedTheme(withScheme: containerScheme)
-    flatButtonStatic.setTitle("Static", for: UIControlState())
+    flatButtonStatic.setTitle("Static", for: UIControl.State())
     flatButtonStatic.sizeToFit()
     flatButtonStatic.translatesAutoresizingMaskIntoConstraints = false
     flatButtonStatic.addTarget(self, action: #selector(tap), for: .touchUpInside)
@@ -51,7 +51,7 @@ class ButtonsCustomFontViewController: UIViewController {
 
     let flatButtonDynamic = MDCButton()
     flatButtonDynamic.applyContainedTheme(withScheme: containerScheme)
-    flatButtonDynamic.setTitle("Dynamic", for: UIControlState())
+    flatButtonDynamic.setTitle("Dynamic", for: UIControl.State())
     flatButtonDynamic.sizeToFit()
     flatButtonDynamic.translatesAutoresizingMaskIntoConstraints = false
     flatButtonDynamic.addTarget(self, action: #selector(tap), for: .touchUpInside)
diff --git a/components/Buttons/examples/ButtonsDynamicTypeViewController.swift b/components/Buttons/examples/ButtonsDynamicTypeViewController.swift
index 0dad5b8d4a8..d155decfb07 100644
--- a/components/Buttons/examples/ButtonsDynamicTypeViewController.swift
+++ b/components/Buttons/examples/ButtonsDynamicTypeViewController.swift
@@ -41,7 +41,7 @@ class ButtonsDynamicTypeViewController: UIViewController {
     flatButtonStatic.applyContainedTheme(withScheme: containerScheme)
     flatButtonStatic.setTitleColor(titleColor, for: .normal)
     flatButtonStatic.setBackgroundColor(backgroundColor, for: .normal)
-    flatButtonStatic.setTitle("Static", for: UIControlState())
+    flatButtonStatic.setTitle("Static", for: UIControl.State())
     flatButtonStatic.sizeToFit()
     flatButtonStatic.translatesAutoresizingMaskIntoConstraints = false
     flatButtonStatic.addTarget(self, action: #selector(tap), for: .touchUpInside)
@@ -52,7 +52,7 @@ class ButtonsDynamicTypeViewController: UIViewController {
     flatButtonDynamic.applyContainedTheme(withScheme: containerScheme)
     flatButtonDynamic.setTitleColor(titleColor, for: .normal)
     flatButtonDynamic.setBackgroundColor(backgroundColor, for: .normal)
-    flatButtonDynamic.setTitle("Dynamic", for: UIControlState())
+    flatButtonDynamic.setTitle("Dynamic", for: UIControl.State())
     flatButtonDynamic.sizeToFit()
     flatButtonDynamic.translatesAutoresizingMaskIntoConstraints = false
     flatButtonDynamic.addTarget(self, action: #selector(tap), for: .touchUpInside)
@@ -64,7 +64,7 @@ class ButtonsDynamicTypeViewController: UIViewController {
     flatButtonDynamicLegacy.applyContainedTheme(withScheme: containerScheme)
     flatButtonDynamicLegacy.setTitleColor(titleColor, for: .normal)
     flatButtonDynamicLegacy.setBackgroundColor(backgroundColor, for: .normal)
-    flatButtonDynamicLegacy.setTitle("Dynamic (legacy)", for: UIControlState())
+    flatButtonDynamicLegacy.setTitle("Dynamic (legacy)", for: UIControl.State())
     flatButtonDynamicLegacy.sizeToFit()
     flatButtonDynamicLegacy.translatesAutoresizingMaskIntoConstraints = false
     flatButtonDynamicLegacy.addTarget(self, action: #selector(tap), for: .touchUpInside)
diff --git a/components/Buttons/examples/ButtonsSimpleExampleSwiftViewController.swift b/components/Buttons/examples/ButtonsSimpleExampleSwiftViewController.swift
index b1f12fdb494..500eb4785f4 100644
--- a/components/Buttons/examples/ButtonsSimpleExampleSwiftViewController.swift
+++ b/components/Buttons/examples/ButtonsSimpleExampleSwiftViewController.swift
@@ -35,30 +35,30 @@ class ButtonsSimpleExampleSwiftViewController: UIViewController {
     
     let containedButton = MDCButton()
     containedButton.applyContainedTheme(withScheme: containerScheme)
-    containedButton.setTitle("Tap Me Too", for: UIControlState())
+    containedButton.setTitle("Tap Me Too", for: UIControl.State())
     containedButton.sizeToFit()
     let containedButtonVerticalInset =
       min(0, -(kMinimumAccessibleButtonSize.height - containedButton.bounds.height) / 2);
     let containedButtonHorizontalInset =
       min(0, -(kMinimumAccessibleButtonSize.width - containedButton.bounds.width) / 2);
     containedButton.hitAreaInsets =
-      UIEdgeInsetsMake(containedButtonVerticalInset, containedButtonHorizontalInset,
-                       containedButtonVerticalInset, containedButtonHorizontalInset);
+      UIEdgeInsets(top: containedButtonVerticalInset, left: containedButtonHorizontalInset,
+                   bottom: containedButtonVerticalInset, right: containedButtonHorizontalInset)
     containedButton.translatesAutoresizingMaskIntoConstraints = false
     containedButton.addTarget(self, action: #selector(tap), for: .touchUpInside)
     view.addSubview(containedButton)
 
     let textButton = MDCButton()
     textButton.applyTextTheme(withScheme: MDCContainerScheme())
-    textButton.setTitle("Touch me", for: UIControlState())
+    textButton.setTitle("Touch me", for: UIControl.State())
     textButton.sizeToFit()
     let textButtonVerticalInset =
       min(0, -(kMinimumAccessibleButtonSize.height - textButton.bounds.height) / 2);
     let textButtonHorizontalInset =
       min(0, -(kMinimumAccessibleButtonSize.width - textButton.bounds.width) / 2);
     textButton.hitAreaInsets =
-      UIEdgeInsetsMake(textButtonVerticalInset, textButtonHorizontalInset,
-                       textButtonVerticalInset, textButtonHorizontalInset);
+      UIEdgeInsets(top: textButtonVerticalInset, left: textButtonHorizontalInset,
+                   bottom: textButtonVerticalInset, right: textButtonHorizontalInset)
     textButton.translatesAutoresizingMaskIntoConstraints = false
     textButton.addTarget(self, action: #selector(tap), for: .touchUpInside)
     view.addSubview(textButton)
diff --git a/components/Buttons/examples/ButtonsStoryboardAndProgrammatic.swift b/components/Buttons/examples/ButtonsStoryboardAndProgrammatic.swift
index df679b9f387..82e964c9859 100644
--- a/components/Buttons/examples/ButtonsStoryboardAndProgrammatic.swift
+++ b/components/Buttons/examples/ButtonsStoryboardAndProgrammatic.swift
@@ -97,11 +97,9 @@ class ButtonsSwiftAndStoryboardController: UIViewController {
 
   private func layoutContainer() {
     let viewLayoutGuide: Any = {
-      #if swift(>=3.2)
-        if #available(iOS 11.0, *) {
-          return view.safeAreaLayoutGuide
-        }
-      #endif
+      if #available(iOS 11.0, *) {
+        return view.safeAreaLayoutGuide
+      }
       return view
     }()
     NSLayoutConstraint.activate([
diff --git a/components/Buttons/examples/FloatingButtonExampleSwiftViewController.swift b/components/Buttons/examples/FloatingButtonExampleSwiftViewController.swift
index 55b956c9283..97fb726cb52 100644
--- a/components/Buttons/examples/FloatingButtonExampleSwiftViewController.swift
+++ b/components/Buttons/examples/FloatingButtonExampleSwiftViewController.swift
@@ -52,7 +52,7 @@ class FloatingButtonExampleSwiftViewController: UIViewController {
     largeIconFloatingButton.translatesAutoresizingMaskIntoConstraints = false
     largeIconFloatingButton.setImage(plusImage36, for: .normal)
     largeIconFloatingButton.accessibilityLabel = "Create"
-    largeIconFloatingButton.setContentEdgeInsets(UIEdgeInsetsMake(-6, -6, -6, 0), for: .default,
+    largeIconFloatingButton.setContentEdgeInsets(UIEdgeInsets(top: -6, left: -6, bottom: -6, right: 0), for: .default,
                                                  in: .expanded)
     largeIconFloatingButton.applySecondaryTheme(withScheme: containerScheme)
 
diff --git a/components/Cards/BUILD b/components/Cards/BUILD
index 7e943dc3b92..379337e1d1c 100644
--- a/components/Cards/BUILD
+++ b/components/Cards/BUILD
@@ -89,7 +89,7 @@ swift_library(
     ]),
     copts = [
         "-swift-version",
-        "3",
+        "4.2",
     ],
     visibility = ["//visibility:private"],
     deps = [
diff --git a/components/Cards/examples/EditReorderCollectionViewController.swift b/components/Cards/examples/EditReorderCollectionViewController.swift
index 6620882d826..79639fac494 100644
--- a/components/Cards/examples/EditReorderCollectionViewController.swift
+++ b/components/Cards/examples/EditReorderCollectionViewController.swift
@@ -83,21 +83,17 @@ class EditReorderCollectionViewController: UIViewController,
       dataSource.append((image: images[ind].image, title: images[ind].title, selected: false))
     }
 
-    #if swift(>=3.2)
-      if #available(iOS 11, *) {
-        let guide = view.safeAreaLayoutGuide
-        NSLayoutConstraint.activate([
-          collectionView.leftAnchor.constraint(equalTo: guide.leftAnchor),
-          collectionView.rightAnchor.constraint(equalTo: guide.rightAnchor),
-          collectionView.topAnchor.constraint(equalTo: view.topAnchor),
-          collectionView.bottomAnchor.constraint(equalTo: guide.bottomAnchor)])
-        collectionView.contentInsetAdjustmentBehavior = .always
-      } else {
-        preiOS11Constraints()
-      }
-    #else
+    if #available(iOS 11, *) {
+      let guide = view.safeAreaLayoutGuide
+      NSLayoutConstraint.activate([
+        collectionView.leftAnchor.constraint(equalTo: guide.leftAnchor),
+        collectionView.rightAnchor.constraint(equalTo: guide.rightAnchor),
+        collectionView.topAnchor.constraint(equalTo: view.topAnchor),
+        collectionView.bottomAnchor.constraint(equalTo: guide.bottomAnchor)])
+      collectionView.contentInsetAdjustmentBehavior = .always
+    } else {
       preiOS11Constraints()
-    #endif
+    }
 
     self.updateTitle()
   }
@@ -124,7 +120,7 @@ class EditReorderCollectionViewController: UIViewController,
     }
   }
 
-  func toggleModes() {
+  @objc func toggleModes() {
     switch toggle {
     case .edit:
       toggle = .reorder
diff --git a/components/Cards/examples/EditReorderShapedCollectionViewController.swift b/components/Cards/examples/EditReorderShapedCollectionViewController.swift
index d05389520b6..818d58559eb 100644
--- a/components/Cards/examples/EditReorderShapedCollectionViewController.swift
+++ b/components/Cards/examples/EditReorderShapedCollectionViewController.swift
@@ -92,22 +92,17 @@ class EditReorderShapedCollectionViewController: UIViewController,
       dataSource.append((i, false))
     }
 
-    #if swift(>=3.2)
-      if #available(iOS 11, *) {
-        let guide = view.safeAreaLayoutGuide
-        NSLayoutConstraint.activate([
-          collectionView.leftAnchor.constraint(equalTo: guide.leftAnchor),
-          collectionView.rightAnchor.constraint(equalTo: guide.rightAnchor),
-          collectionView.topAnchor.constraint(equalTo: view.topAnchor),
-          collectionView.bottomAnchor.constraint(equalTo: guide.bottomAnchor)])
-        collectionView.contentInsetAdjustmentBehavior = .always
-      } else {
-        preiOS11Constraints()
-      }
-    #else
+    if #available(iOS 11, *) {
+      let guide = view.safeAreaLayoutGuide
+      NSLayoutConstraint.activate([
+        collectionView.leftAnchor.constraint(equalTo: guide.leftAnchor),
+        collectionView.rightAnchor.constraint(equalTo: guide.rightAnchor),
+        collectionView.topAnchor.constraint(equalTo: view.topAnchor),
+        collectionView.bottomAnchor.constraint(equalTo: guide.bottomAnchor)])
+      collectionView.contentInsetAdjustmentBehavior = .always
+    } else {
       preiOS11Constraints()
-    #endif
-
+    }
   }
 
   func preiOS11Constraints() {
@@ -121,7 +116,7 @@ class EditReorderShapedCollectionViewController: UIViewController,
                                                             views: ["view": collectionView]));
   }
 
-  func toggleModes() {
+  @objc func toggleModes() {
     if toggle == .edit {
       toggle = .reorder
       navigationItem.rightBarButtonItem?.title = "Reorder"
diff --git a/components/Cards/examples/ShapedCardViewController.swift b/components/Cards/examples/ShapedCardViewController.swift
index 41f057d704b..616e046823d 100644
--- a/components/Cards/examples/ShapedCardViewController.swift
+++ b/components/Cards/examples/ShapedCardViewController.swift
@@ -148,7 +148,7 @@ class ShapedCardViewController: UIViewController {
     secondarySlider.sendActions(for: .valueChanged)
   }
 
-  func didChangeSliderValue(slider: UISlider) {
+  @objc func didChangeSliderValue(slider: UISlider) {
     if let shape = card.shapeGenerator as? MDCRectangleShapeGenerator {
       if slider == primarySlider {
         let cutCornerTreatment = MDCCutCornerTreatment(cut: CGFloat(slider.value))
@@ -170,7 +170,7 @@ class ShapedCardViewController: UIViewController {
     return super.traitCollection
   }
 
-  func changeShape() {
+  @objc func changeShape() {
     primarySlider.isHidden = true
     secondarySlider.isHidden = true
     switch(card.shapeGenerator) {
@@ -178,16 +178,16 @@ class ShapedCardViewController: UIViewController {
       let shapeGenerator = MDCCurvedRectShapeGenerator(cornerSize: CGSize(width: 50,
                                                                           height: 100))
       card.shapeGenerator = shapeGenerator
-      card.contentView.layoutMargins = UIEdgeInsetsMake(0, 40, 0, 40)
+      card.contentView.layoutMargins = UIEdgeInsets(top: 0, left: 40, bottom: 0, right: 40)
     case is MDCCurvedRectShapeGenerator:
       let shapeGenerator = MDCPillShapeGenerator()
       card.shapeGenerator = shapeGenerator
-      card.contentView.layoutMargins = UIEdgeInsetsMake(0, 80, 0, 80)
+      card.contentView.layoutMargins = UIEdgeInsets(top: 0, left: 80, bottom: 0, right: 80)
     case is MDCPillShapeGenerator:
       let shapeGenerator = MDCSlantedRectShapeGenerator()
       shapeGenerator.slant = 40
       card.shapeGenerator = shapeGenerator
-      card.contentView.layoutMargins = UIEdgeInsetsMake(0, 40, 0, 40)
+      card.contentView.layoutMargins = UIEdgeInsets(top: 0, left: 40, bottom: 0, right: 40)
     case is MDCSlantedRectShapeGenerator:
       fallthrough
     default:
@@ -206,7 +206,7 @@ class ShapedCardViewController: UIViewController {
     let triangleEdgeTreatment = MDCTriangleEdgeTreatment(size: 0, style: MDCTriangleEdgeStyleCut)
     shapeGenerator.setEdges(triangleEdgeTreatment)
     card.shapeGenerator = shapeGenerator
-    card.contentView.layoutMargins = UIEdgeInsetsMake(0, 5, 0, 5)
+    card.contentView.layoutMargins = UIEdgeInsets(top: 0, left: 5, bottom: 0, right: 5)
   }
 }
 
diff --git a/components/Cards/examples/supplemental/CardEditReorderCollectionCell.swift b/components/Cards/examples/supplemental/CardEditReorderCollectionCell.swift
index 5c5a9c4f34e..85f4690702c 100644
--- a/components/Cards/examples/supplemental/CardEditReorderCollectionCell.swift
+++ b/components/Cards/examples/supplemental/CardEditReorderCollectionCell.swift
@@ -47,7 +47,8 @@ class CardEditReorderCollectionCell: MDCCardCollectionCell {
 
     self.contentView.addSubview(imageView)
     self.contentView.addSubview(titleLabel)
-    titleLabel.setContentCompressionResistancePriority(800, for: .vertical)
+    titleLabel.setContentCompressionResistancePriority(UILayoutPriority(rawValue: 800),
+                                                       for: .vertical)
 
     addConstraints()
   }
diff --git a/components/Cards/tests/unit/Theming/CardsMaterialThemingTests.swift b/components/Cards/tests/unit/Theming/CardsMaterialThemingTests.swift
index db961733151..66c1cec2ee6 100644
--- a/components/Cards/tests/unit/Theming/CardsMaterialThemingTests.swift
+++ b/components/Cards/tests/unit/Theming/CardsMaterialThemingTests.swift
@@ -99,7 +99,7 @@ class CardsMaterialThemingTests: XCTestCase {
     }
 
     // Test remaining properties
-    [UIControlState.normal, .highlighted, .selected, .disabled].forEach {
+    [UIControl.State.normal, .highlighted, .selected, .disabled].forEach {
       XCTAssertEqual(card.shadowElevation(for: $0),
                      ShadowElevation.none,
                      "Shadow elevation incorrect for state \($0)")
diff --git a/components/ChipTextField/examples/UITextFieldWithChipsExample.swift b/components/ChipTextField/examples/UITextFieldWithChipsExample.swift
index 378f96455fd..b3554bcf6ac 100644
--- a/components/ChipTextField/examples/UITextFieldWithChipsExample.swift
+++ b/components/ChipTextField/examples/UITextFieldWithChipsExample.swift
@@ -119,7 +119,7 @@ class UITextFieldWithChipsExample: UIViewController {
         //lastmax = lastLabel.frame.maxX
       } else {
         leadingConstraint = label.leadingAnchor.constraint(equalTo: leftView.leadingAnchor)
-        leadingConstraint?.priority = UILayoutPriorityDefaultLow
+        leadingConstraint?.priority = UILayoutPriority.defaultLow
         leadingConstraint?.isActive = true
       }
     } else {
@@ -222,7 +222,7 @@ private class InsetTextField: UITextField {
   // text bounds
   override func textRect(forBounds bounds: CGRect) -> CGRect {
     let superbounds = super.textRect(forBounds: bounds)
-    var newbounds = UIEdgeInsetsInsetRect(superbounds, insetRect)
+    var newbounds = superbounds.inset(by: insetRect)
     newbounds.origin.x = insetX
     return newbounds
   }
@@ -230,7 +230,7 @@ private class InsetTextField: UITextField {
   // text bounds while editing
   override func editingRect(forBounds bounds: CGRect) -> CGRect {
     let superbounds = super.editingRect(forBounds: bounds)
-    var newbounds = UIEdgeInsetsInsetRect(superbounds, insetRect)
+    var newbounds = superbounds.inset(by: insetRect)
     newbounds.origin.x = insetX
     return newbounds
   }
@@ -252,14 +252,14 @@ class PlainTextField: UITextField {
   // text bounds
   override func textRect(forBounds bounds: CGRect) -> CGRect {
     let superbounds = super.textRect(forBounds: bounds)
-    let newbounds = UIEdgeInsetsInsetRect(superbounds, insetRect)
+    let newbounds = superbounds.inset(by: insetRect)
     return newbounds
   }
 
   // text bounds while editing
   override func editingRect(forBounds bounds: CGRect) -> CGRect {
     let superbounds = super.editingRect(forBounds: bounds)
-    let newbounds = UIEdgeInsetsInsetRect(superbounds, insetRect)
+    let newbounds = superbounds.inset(by: insetRect)
     return newbounds
   }
 }
diff --git a/components/Chips/BUILD b/components/Chips/BUILD
index 8cf98b32e39..b48ae492bd6 100644
--- a/components/Chips/BUILD
+++ b/components/Chips/BUILD
@@ -152,7 +152,7 @@ swift_library(
     ]),
     copts = [
         "-swift-version",
-        "3",
+        "4.2",
     ],
     visibility = ["//visibility:private"],
     deps = [
diff --git a/components/Chips/examples/ChipsFieldDeleteEnabledViewController.swift b/components/Chips/examples/ChipsFieldDeleteEnabledViewController.swift
index c563be42378..a47461c4288 100644
--- a/components/Chips/examples/ChipsFieldDeleteEnabledViewController.swift
+++ b/components/Chips/examples/ChipsFieldDeleteEnabledViewController.swift
@@ -49,7 +49,7 @@ class ChipsFieldDeleteEnabledViewController : UIViewController, MDCChipFieldDele
 
     var frame = view.bounds
     if #available(iOS 11.0, *) {
-      frame = UIEdgeInsetsInsetRect(frame, view.safeAreaInsets)
+      frame = frame.inset(by: view.safeAreaInsets)
     }
     frame.size = chipField.sizeThatFits(frame.size)
     chipField.frame = frame
@@ -63,7 +63,7 @@ class ChipsFieldDeleteEnabledViewController : UIViewController, MDCChipFieldDele
     chip.applyTheme(withScheme: containerScheming)
     chip.sizeToFit()
     let chipVerticalInset = min(0, chip.bounds.height - 48 / 2)
-    chip.hitAreaInsets = UIEdgeInsetsMake(chipVerticalInset, 0, chipVerticalInset, 0)
+    chip.hitAreaInsets = UIEdgeInsets(top: chipVerticalInset, left: 0, bottom: chipVerticalInset, right: 0)
   }
 }
 // MARK - Catalog by Convention
diff --git a/components/Dialogs/BUILD b/components/Dialogs/BUILD
index 56511db01e1..780ae839fee 100644
--- a/components/Dialogs/BUILD
+++ b/components/Dialogs/BUILD
@@ -164,7 +164,7 @@ swift_library(
     ]),
     copts = [
         "-swift-version",
-        "3",
+        "4.2",
     ],
     visibility = ["//visibility:private"],
     deps = [
diff --git a/components/Dialogs/examples/DialogsAlertComparisonExample.swift b/components/Dialogs/examples/DialogsAlertComparisonExample.swift
index 3a9e328461f..818f9b88b73 100644
--- a/components/Dialogs/examples/DialogsAlertComparisonExample.swift
+++ b/components/Dialogs/examples/DialogsAlertComparisonExample.swift
@@ -87,7 +87,7 @@ class DialogsAlertComparisonExample: UIViewController {
       ])
 
       uikitButton.translatesAutoresizingMaskIntoConstraints = false
-      uikitButton.setTitle("UIKit Alert", for: UIControlState())
+      uikitButton.setTitle("UIKit Alert", for: UIControl.State())
       uikitButton.setTitleColor(UIColor(white: 0.1, alpha:1), for: .normal)
       uikitButton.sizeToFit()
       uikitButton.addTarget(self, action: #selector(tapUIKit), for: .touchUpInside)
diff --git a/components/Dialogs/examples/DialogsCustomShadowExampleViewController.swift b/components/Dialogs/examples/DialogsCustomShadowExampleViewController.swift
index 0599c650226..a0ae14fb6b5 100644
--- a/components/Dialogs/examples/DialogsCustomShadowExampleViewController.swift
+++ b/components/Dialogs/examples/DialogsCustomShadowExampleViewController.swift
@@ -70,8 +70,8 @@ class DialogsCustomShadowExampleViewController: UIViewController {
 
     view.backgroundColor = containerScheme.colorScheme.backgroundColor
 
-    textButton.setTitle("PRESENT ALERT", for: UIControlState())
-    textButton.setTitleColor(UIColor(white: 0.1, alpha:1), for: UIControlState())
+    textButton.setTitle("PRESENT ALERT", for: UIControl.State())
+    textButton.setTitleColor(UIColor(white: 0.1, alpha:1), for: UIControl.State())
     textButton.sizeToFit()
     textButton.translatesAutoresizingMaskIntoConstraints = false
     textButton.addTarget(self, action: #selector(tap), for: .touchUpInside)
diff --git a/components/Dialogs/examples/DialogsLongAlertExampleViewController.swift b/components/Dialogs/examples/DialogsLongAlertExampleViewController.swift
index 67675b8bc5d..c21f1d4c5d7 100644
--- a/components/Dialogs/examples/DialogsLongAlertExampleViewController.swift
+++ b/components/Dialogs/examples/DialogsLongAlertExampleViewController.swift
@@ -30,8 +30,8 @@ class DialogsLongAlertExampleViewController: UIViewController {
 
     view.backgroundColor = containerScheme.colorScheme.backgroundColor
 
-    textButton.setTitle("PRESENT ALERT", for: UIControlState())
-    textButton.setTitleColor(UIColor(white: 0.1, alpha:1), for: UIControlState())
+    textButton.setTitle("PRESENT ALERT", for: UIControl.State())
+    textButton.setTitleColor(UIColor(white: 0.1, alpha:1), for: UIControl.State())
     textButton.sizeToFit()
     textButton.translatesAutoresizingMaskIntoConstraints = false
     textButton.addTarget(self, action: #selector(tap), for: .touchUpInside)
diff --git a/components/FeatureHighlight/examples/FeatureHightlightTypicalUseViewController.swift b/components/FeatureHighlight/examples/FeatureHightlightTypicalUseViewController.swift
index e1a36e7fb7d..1350aca0dec 100644
--- a/components/FeatureHighlight/examples/FeatureHightlightTypicalUseViewController.swift
+++ b/components/FeatureHighlight/examples/FeatureHightlightTypicalUseViewController.swift
@@ -56,7 +56,7 @@ class FeatureHighlightSwiftViewController: UIViewController {
     featureButton.frame.origin.y = view.bounds.height / 2 - featureButton.frame.height / 2
   }
 
-  func showFeatureHighlight() {
+  @objc func showFeatureHighlight() {
     let vc = MDCFeatureHighlightViewController(highlightedView: featureButton,
                                                completion: nil)
     MDCFeatureHighlightColorThemer.applySemanticColorScheme(colorScheme, to: vc)
diff --git a/components/FlexibleHeader/BUILD b/components/FlexibleHeader/BUILD
index a00a800e8f2..873cd9b4633 100644
--- a/components/FlexibleHeader/BUILD
+++ b/components/FlexibleHeader/BUILD
@@ -83,7 +83,7 @@ swift_library(
     srcs = glob(["tests/unit/*.swift"]),
     copts = [
         "-swift-version",
-        "3",
+        "4.2",
     ],
     visibility = ["//visibility:private"],
     deps = [
diff --git a/components/FlexibleHeader/tests/unit/FlexibleHeaderControllerIssue176Tests.swift b/components/FlexibleHeader/tests/unit/FlexibleHeaderControllerIssue176Tests.swift
index 358dece1ce4..d7907b685a2 100644
--- a/components/FlexibleHeader/tests/unit/FlexibleHeaderControllerIssue176Tests.swift
+++ b/components/FlexibleHeader/tests/unit/FlexibleHeaderControllerIssue176Tests.swift
@@ -37,11 +37,7 @@ class FlexibleHeaderControllerIssue176Tests: XCTestCase {
   }
 
   func registerToParentViewController(_ parent: UIViewController) {
-    #if swift(>=4.2)
-      parent.addChild(fhvc)
-    #else
-      parent.addChildViewController(fhvc)
-    #endif
+    parent.addChild(fhvc)
     parent.view.addSubview(fhvc.view)
   }
 
@@ -50,11 +46,7 @@ class FlexibleHeaderControllerIssue176Tests: XCTestCase {
     self.registerToParentViewController(parentVc)
 
     // NOTE: No tracking scroll view
-    #if swift(>=4.2)
     fhvc.didMove(toParent: parentVc)
-    #else
-    fhvc.didMove(toParentViewController: parentVc)
-    #endif
 
     XCTAssertEqual(fhvc.view.bounds.size.height, fhvc.headerView.minimumHeight)
   }
@@ -71,11 +63,7 @@ class FlexibleHeaderControllerIssue176Tests: XCTestCase {
 
     fhvc.headerView.trackingScrollView = parentVc.tableView
 
-    #if swift(>=4.2)
     fhvc.didMove(toParent: parentVc)
-    #else
-    fhvc.didMove(toParentViewController: parentVc)
-    #endif
 
     XCTAssertEqual(fhvc.headerView.trackingScrollView!.contentOffset.y,
                    -fhvc.headerView.maximumHeight)
diff --git a/components/FlexibleHeader/tests/unit/FlexibleHeaderControllerIssue279Tests.swift b/components/FlexibleHeader/tests/unit/FlexibleHeaderControllerIssue279Tests.swift
index 39e9d20f28b..c6dfe82e759 100644
--- a/components/FlexibleHeader/tests/unit/FlexibleHeaderControllerIssue279Tests.swift
+++ b/components/FlexibleHeader/tests/unit/FlexibleHeaderControllerIssue279Tests.swift
@@ -30,20 +30,12 @@ class FlexibleHeaderControllerIssue279Tests: XCTestCase {
     fhvc = MDCFlexibleHeaderViewController()
 
     tableViewController = UITableViewController()
-    #if swift(>=4.2)
     tableViewController.addChild(fhvc)
-    #else
-    tableViewController.addChildViewController(fhvc)
-    #endif
     tableViewController.view.addSubview(fhvc.headerView)
 
     fhvc.headerView.trackingScrollView = tableViewController.tableView
 
-    #if swift(>=4.2)
     fhvc.didMove(toParent: tableViewController)
-    #else
-    fhvc.didMove(toParentViewController: tableViewController)
-    #endif
   }
 
   override func tearDown() {
diff --git a/components/FlexibleHeader/tests/unit/FlexibleHeaderInjectionLegacyTopLayoutGuideTests.swift b/components/FlexibleHeader/tests/unit/FlexibleHeaderInjectionLegacyTopLayoutGuideTests.swift
index 24703080be9..f2030b6e317 100644
--- a/components/FlexibleHeader/tests/unit/FlexibleHeaderInjectionLegacyTopLayoutGuideTests.swift
+++ b/components/FlexibleHeader/tests/unit/FlexibleHeaderInjectionLegacyTopLayoutGuideTests.swift
@@ -42,25 +42,15 @@ class FlexibleHeaderInjectionLegacyTopLayoutGuideTests: XCTestCase {
   func testNoScrollViewTopLayoutGuideEqualsZero() {
     // Given
     let contentViewController = UIViewController()
-    #if swift(>=4.2)
     contentViewController.addChild(fhvc)
-    #else
-    contentViewController.addChildViewController(fhvc)
-    #endif
     contentViewController.view.addSubview(fhvc.view)
-    #if swift(>=4.2)
     fhvc.didMove(toParent: contentViewController)
-    #else
-    fhvc.didMove(toParentViewController: contentViewController)
-    #endif
 
     // Then
     XCTAssertEqual(contentViewController.topLayoutGuide.length, 0)
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       XCTAssertEqual(contentViewController.additionalSafeAreaInsets.top, 0)
     }
-    #endif
   }
 
   // MARK: Untracked table view
@@ -68,26 +58,16 @@ class FlexibleHeaderInjectionLegacyTopLayoutGuideTests: XCTestCase {
   func testUntrackedTableViewTopLayoutGuideEqualsZero() {
     // Given
     let contentViewController = UITableViewController()
-    #if swift(>=4.2)
     contentViewController.addChild(fhvc)
-    #else
-    contentViewController.addChildViewController(fhvc)
-    #endif
     contentViewController.view.addSubview(fhvc.view)
-    #if swift(>=4.2)
     fhvc.didMove(toParent: contentViewController)
-    #else
-    fhvc.didMove(toParentViewController: contentViewController)
-    #endif
 
     // Then
     XCTAssertEqual(contentViewController.topLayoutGuide.length, 0)
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       XCTAssertEqual(contentViewController.additionalSafeAreaInsets.top, 0)
       XCTAssertEqual(contentViewController.tableView.adjustedContentInset.top, 0)
     }
-    #endif
   }
 
   // MARK: Tracked table view
@@ -96,28 +76,18 @@ class FlexibleHeaderInjectionLegacyTopLayoutGuideTests: XCTestCase {
     // Given
     let contentViewController = UITableViewController()
     fhvc.headerView.trackingScrollView = contentViewController.tableView
-    #if swift(>=4.2)
     contentViewController.addChild(fhvc)
-    #else
-    contentViewController.addChildViewController(fhvc)
-    #endif
     contentViewController.view.addSubview(fhvc.view)
-    #if swift(>=4.2)
     fhvc.didMove(toParent: contentViewController)
-    #else
-    fhvc.didMove(toParentViewController: contentViewController)
-    #endif
     fhvc.headerView.trackingScrollDidScroll()
 
     // Then
     XCTAssertEqual(contentViewController.topLayoutGuide.length, 0)
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       XCTAssertEqual(contentViewController.additionalSafeAreaInsets.top, 0)
       XCTAssertEqual(contentViewController.tableView.adjustedContentInset.top,
                      fhvc.headerView.maximumHeight + MDCDeviceTopSafeAreaInset())
     }
-    #endif
   }
 
   func testTrackedTableViewTopLayoutGuideEqualsBottomEdgeOfHeaderViewAfterScrolling() {
@@ -127,17 +97,9 @@ class FlexibleHeaderInjectionLegacyTopLayoutGuideTests: XCTestCase {
       CGSize(width: contentViewController.tableView.bounds.width,
              height: contentViewController.tableView.bounds.height * 2)
     fhvc.headerView.trackingScrollView = contentViewController.tableView
-    #if swift(>=4.2)
     contentViewController.addChild(fhvc)
-    #else
-    contentViewController.addChildViewController(fhvc)
-    #endif
     contentViewController.view.addSubview(fhvc.view)
-    #if swift(>=4.2)
     fhvc.didMove(toParent: contentViewController)
-    #else
-    fhvc.didMove(toParentViewController: contentViewController)
-    #endif
     fhvc.headerView.trackingScrollDidScroll()
     contentViewController.tableView.contentOffset =
       CGPoint(x: 0, y: -contentViewController.tableView.contentInset.top)
@@ -146,13 +108,11 @@ class FlexibleHeaderInjectionLegacyTopLayoutGuideTests: XCTestCase {
     // Then
     XCTAssertEqual(contentViewController.topLayoutGuide.length,
                    fhvc.headerView.frame.maxY)
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       XCTAssertEqual(contentViewController.additionalSafeAreaInsets.top, 0)
       XCTAssertEqual(contentViewController.tableView.adjustedContentInset.top,
                      fhvc.headerView.maximumHeight + MDCDeviceTopSafeAreaInset())
     }
-    #endif
   }
 
   // MARK: Untracked collection view
@@ -161,26 +121,16 @@ class FlexibleHeaderInjectionLegacyTopLayoutGuideTests: XCTestCase {
     // Given
     let flow = UICollectionViewFlowLayout()
     let contentViewController = UICollectionViewController(collectionViewLayout: flow)
-    #if swift(>=4.2)
     contentViewController.addChild(fhvc)
-    #else
-    contentViewController.addChildViewController(fhvc)
-    #endif
     contentViewController.view.addSubview(fhvc.view)
-    #if swift(>=4.2)
     fhvc.didMove(toParent: contentViewController)
-    #else
-    fhvc.didMove(toParentViewController: contentViewController)
-    #endif
 
     // Then
     XCTAssertEqual(contentViewController.topLayoutGuide.length, 0)
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       XCTAssertEqual(contentViewController.additionalSafeAreaInsets.top, 0)
       XCTAssertEqual(contentViewController.collectionView!.adjustedContentInset.top, 0)
     }
-    #endif
   }
 
   // MARK: Tracked collection view view
@@ -190,28 +140,18 @@ class FlexibleHeaderInjectionLegacyTopLayoutGuideTests: XCTestCase {
     let flow = UICollectionViewFlowLayout()
     let contentViewController = UICollectionViewController(collectionViewLayout: flow)
     fhvc.headerView.trackingScrollView = contentViewController.collectionView
-    #if swift(>=4.2)
     contentViewController.addChild(fhvc)
-    #else
-    contentViewController.addChildViewController(fhvc)
-    #endif
     contentViewController.view.addSubview(fhvc.view)
-    #if swift(>=4.2)
     fhvc.didMove(toParent: contentViewController)
-    #else
-    fhvc.didMove(toParentViewController: contentViewController)
-    #endif
     fhvc.headerView.trackingScrollDidScroll()
 
     // Then
     XCTAssertEqual(contentViewController.topLayoutGuide.length, 0)
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       XCTAssertEqual(contentViewController.additionalSafeAreaInsets.top, 0)
       XCTAssertEqual(contentViewController.collectionView!.adjustedContentInset.top,
                      fhvc.headerView.maximumHeight + MDCDeviceTopSafeAreaInset())
     }
-    #endif
   }
 
   func testTrackedCollectionViewTopLayoutGuideEqualsZeroAfterScrolling() {
@@ -222,17 +162,9 @@ class FlexibleHeaderInjectionLegacyTopLayoutGuideTests: XCTestCase {
       CGSize(width: contentViewController.collectionView!.bounds.width,
              height: contentViewController.collectionView!.bounds.height * 2)
     fhvc.headerView.trackingScrollView = contentViewController.collectionView!
-    #if swift(>=4.2)
     contentViewController.addChild(fhvc)
-    #else
-    contentViewController.addChildViewController(fhvc)
-    #endif
     contentViewController.view.addSubview(fhvc.view)
-    #if swift(>=4.2)
     fhvc.didMove(toParent: contentViewController)
-    #else
-    fhvc.didMove(toParentViewController: contentViewController)
-    #endif
     fhvc.headerView.trackingScrollDidScroll()
     contentViewController.collectionView!.contentOffset =
       CGPoint(x: 0, y: -contentViewController.collectionView!.contentInset.top)
@@ -240,13 +172,11 @@ class FlexibleHeaderInjectionLegacyTopLayoutGuideTests: XCTestCase {
 
     // Then
     XCTAssertEqual(contentViewController.topLayoutGuide.length, 0)
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       XCTAssertEqual(contentViewController.additionalSafeAreaInsets.top, 0)
       XCTAssertEqual(contentViewController.collectionView!.adjustedContentInset.top,
                      fhvc.headerView.maximumHeight + MDCDeviceTopSafeAreaInset())
     }
-    #endif
   }
 
 }
diff --git a/components/FlexibleHeader/tests/unit/FlexibleHeaderInjectionTopLayoutGuideTests.swift b/components/FlexibleHeader/tests/unit/FlexibleHeaderInjectionTopLayoutGuideTests.swift
index e029dc3e7aa..0b873a3c2c8 100644
--- a/components/FlexibleHeader/tests/unit/FlexibleHeaderInjectionTopLayoutGuideTests.swift
+++ b/components/FlexibleHeader/tests/unit/FlexibleHeaderInjectionTopLayoutGuideTests.swift
@@ -40,27 +40,17 @@ class FlexibleHeaderInjectionTopLayoutGuideTests: XCTestCase {
   func testTopLayoutGuideIsUnaffactedWithNoTopLayoutGuideViewController() {
     // Given
     let contentViewController = UIViewController()
-    #if swift(>=4.2)
     contentViewController.addChild(fhvc)
-    #else
-    contentViewController.addChildViewController(fhvc)
-    #endif
     contentViewController.view.addSubview(fhvc.view)
     fhvc.isTopLayoutGuideAdjustmentEnabled = true
     fhvc.topLayoutGuideViewController = nil
-    #if swift(>=4.2)
     fhvc.didMove(toParent: contentViewController)
-    #else
-    fhvc.didMove(toParentViewController: contentViewController)
-    #endif
 
     // Then
     XCTAssertEqual(contentViewController.topLayoutGuide.length, 0)
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       XCTAssertEqual(contentViewController.additionalSafeAreaInsets.top, 0)
     }
-    #endif
   }
 
   // MARK: No scroll view
@@ -68,27 +58,17 @@ class FlexibleHeaderInjectionTopLayoutGuideTests: XCTestCase {
   func testNoScrollViewTopLayoutGuideEqualsBottomEdgeOfHeaderView() {
     // Given
     let contentViewController = UIViewController()
-    #if swift(>=4.2)
     contentViewController.addChild(fhvc)
-    #else
-    contentViewController.addChildViewController(fhvc)
-    #endif
     contentViewController.view.addSubview(fhvc.view)
     fhvc.topLayoutGuideViewController = contentViewController
-    #if swift(>=4.2)
     fhvc.didMove(toParent: contentViewController)
-    #else
-    fhvc.didMove(toParentViewController: contentViewController)
-    #endif
 
     // Then
     XCTAssertEqual(contentViewController.topLayoutGuide.length, fhvc.headerView.frame.maxY)
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       XCTAssertEqual(contentViewController.additionalSafeAreaInsets.top,
                      fhvc.headerView.frame.maxY - MDCDeviceTopSafeAreaInset())
     }
-    #endif
   }
 
   // MARK: Untracked table view
@@ -96,68 +76,46 @@ class FlexibleHeaderInjectionTopLayoutGuideTests: XCTestCase {
   func testUntrackedTableViewTopLayoutGuideEqualsBottomEdgeOfHeaderView() {
     // Given
     let contentViewController = UITableViewController()
-    #if swift(>=4.2)
     contentViewController.addChild(fhvc)
-    #else
-    contentViewController.addChildViewController(fhvc)
-    #endif
     contentViewController.view.addSubview(fhvc.view)
     fhvc.topLayoutGuideViewController = contentViewController
-    #if swift(>=4.2)
     fhvc.didMove(toParent: contentViewController)
-    #else
-    fhvc.didMove(toParentViewController: contentViewController)
-    #endif
 
     // Then
     XCTAssertEqual(contentViewController.topLayoutGuide.length, fhvc.headerView.frame.maxY)
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       XCTAssertEqual(contentViewController.additionalSafeAreaInsets.top,
                      fhvc.headerView.frame.maxY - MDCDeviceTopSafeAreaInset())
       XCTAssertEqual(contentViewController.tableView.adjustedContentInset.top, 0)
     }
-    #endif
   }
 
   func testTrackingAnUntrackedTableViewTopLayoutGuideEqualsBottomEdgeOfHeaderView() {
     // Given
     let contentViewController = UITableViewController()
-    #if swift(>=4.2)
     contentViewController.addChild(fhvc)
-    #else
-    contentViewController.addChildViewController(fhvc)
-    #endif
     contentViewController.view.addSubview(fhvc.view)
     fhvc.topLayoutGuideViewController = contentViewController
-    #if swift(>=4.2)
     fhvc.didMove(toParent: contentViewController)
-    #else
-    fhvc.didMove(toParentViewController: contentViewController)
-    #endif
 
     // Then
     XCTAssertEqual(contentViewController.topLayoutGuide.length, fhvc.headerView.frame.maxY)
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       XCTAssertEqual(contentViewController.additionalSafeAreaInsets.top,
                      fhvc.headerView.frame.maxY - MDCDeviceTopSafeAreaInset())
       XCTAssertEqual(contentViewController.tableView.adjustedContentInset.top, 0)
     }
-    #endif
 
     // And then when
     fhvc.headerView.trackingScrollView = contentViewController.tableView
 
     // Then
     XCTAssertEqual(contentViewController.topLayoutGuide.length, fhvc.headerView.frame.maxY)
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       XCTAssertEqual(contentViewController.additionalSafeAreaInsets.top, 0)
       XCTAssertEqual(contentViewController.tableView.adjustedContentInset.top,
                      fhvc.headerView.maximumHeight + MDCDeviceTopSafeAreaInset())
     }
-    #endif
   }
 
   // MARK: Tracked table view
@@ -166,29 +124,19 @@ class FlexibleHeaderInjectionTopLayoutGuideTests: XCTestCase {
     // Given
     let contentViewController = UITableViewController()
     fhvc.headerView.trackingScrollView = contentViewController.tableView
-    #if swift(>=4.2)
     contentViewController.addChild(fhvc)
-    #else
-    contentViewController.addChildViewController(fhvc)
-    #endif
     contentViewController.view.addSubview(fhvc.view)
     fhvc.topLayoutGuideViewController = contentViewController
-    #if swift(>=4.2)
     fhvc.didMove(toParent: contentViewController)
-    #else
-    fhvc.didMove(toParentViewController: contentViewController)
-    #endif
     fhvc.headerView.trackingScrollDidScroll()
 
     // Then
     XCTAssertEqual(contentViewController.topLayoutGuide.length, fhvc.headerView.frame.maxY)
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       XCTAssertEqual(contentViewController.additionalSafeAreaInsets.top, 0)
       XCTAssertEqual(contentViewController.tableView.adjustedContentInset.top,
                      fhvc.headerView.maximumHeight + MDCDeviceTopSafeAreaInset())
     }
-    #endif
   }
 
   func testTrackedTableViewTopLayoutGuideEqualsBottomEdgeOfHeaderViewAfterScrolling() {
@@ -198,18 +146,10 @@ class FlexibleHeaderInjectionTopLayoutGuideTests: XCTestCase {
       CGSize(width: contentViewController.tableView.bounds.width,
              height: contentViewController.tableView.bounds.height * 2)
     fhvc.headerView.trackingScrollView = contentViewController.tableView
-    #if swift(>=4.2)
     contentViewController.addChild(fhvc)
-    #else
-    contentViewController.addChildViewController(fhvc)
-    #endif
     contentViewController.view.addSubview(fhvc.view)
     fhvc.topLayoutGuideViewController = contentViewController
-    #if swift(>=4.2)
     fhvc.didMove(toParent: contentViewController)
-    #else
-    fhvc.didMove(toParentViewController: contentViewController)
-    #endif
     fhvc.headerView.trackingScrollDidScroll()
     contentViewController.tableView.contentOffset =
       CGPoint(x: 0, y: -contentViewController.tableView.contentInset.top)
@@ -218,13 +158,11 @@ class FlexibleHeaderInjectionTopLayoutGuideTests: XCTestCase {
     // Then
     XCTAssertEqual(contentViewController.topLayoutGuide.length,
                    fhvc.headerView.frame.maxY)
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       XCTAssertEqual(contentViewController.additionalSafeAreaInsets.top, 0)
       XCTAssertEqual(contentViewController.tableView.adjustedContentInset.top,
                      fhvc.headerView.maximumHeight + MDCDeviceTopSafeAreaInset())
     }
-    #endif
   }
 
   // MARK: Untracked collection view
@@ -233,28 +171,18 @@ class FlexibleHeaderInjectionTopLayoutGuideTests: XCTestCase {
     // Given
     let flow = UICollectionViewFlowLayout()
     let contentViewController = UICollectionViewController(collectionViewLayout: flow)
-    #if swift(>=4.2)
     contentViewController.addChild(fhvc)
-    #else
-    contentViewController.addChildViewController(fhvc)
-    #endif
     contentViewController.view.addSubview(fhvc.view)
     fhvc.topLayoutGuideViewController = contentViewController
-    #if swift(>=4.2)
     fhvc.didMove(toParent: contentViewController)
-    #else
-    fhvc.didMove(toParentViewController: contentViewController)
-    #endif
 
     // Then
     XCTAssertEqual(contentViewController.topLayoutGuide.length, fhvc.headerView.frame.maxY)
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       XCTAssertEqual(contentViewController.additionalSafeAreaInsets.top,
                      fhvc.headerView.frame.maxY - MDCDeviceTopSafeAreaInset())
       XCTAssertEqual(contentViewController.collectionView!.adjustedContentInset.top, 0)
     }
-    #endif
   }
 
   // MARK: Tracked collection view view
@@ -264,29 +192,19 @@ class FlexibleHeaderInjectionTopLayoutGuideTests: XCTestCase {
     let flow = UICollectionViewFlowLayout()
     let contentViewController = UICollectionViewController(collectionViewLayout: flow)
     fhvc.headerView.trackingScrollView = contentViewController.collectionView
-    #if swift(>=4.2)
     contentViewController.addChild(fhvc)
-    #else
-    contentViewController.addChildViewController(fhvc)
-    #endif
     contentViewController.view.addSubview(fhvc.view)
     fhvc.topLayoutGuideViewController = contentViewController
-    #if swift(>=4.2)
     fhvc.didMove(toParent: contentViewController)
-    #else
-    fhvc.didMove(toParentViewController: contentViewController)
-    #endif
     fhvc.headerView.trackingScrollDidScroll()
 
     // Then
     XCTAssertEqual(contentViewController.topLayoutGuide.length, fhvc.headerView.frame.maxY)
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       XCTAssertEqual(contentViewController.additionalSafeAreaInsets.top, 0)
       XCTAssertEqual(contentViewController.collectionView!.adjustedContentInset.top,
                      fhvc.headerView.maximumHeight + MDCDeviceTopSafeAreaInset())
     }
-    #endif
   }
 
   func testTrackedCollectionViewTopLayoutGuideEqualsBottomEdgeOfHeaderViewAfterScrolling() {
@@ -297,18 +215,10 @@ class FlexibleHeaderInjectionTopLayoutGuideTests: XCTestCase {
       CGSize(width: contentViewController.collectionView!.bounds.width,
              height: contentViewController.collectionView!.bounds.height * 2)
     fhvc.headerView.trackingScrollView = contentViewController.collectionView!
-    #if swift(>=4.2)
     contentViewController.addChild(fhvc)
-    #else
-    contentViewController.addChildViewController(fhvc)
-    #endif
     contentViewController.view.addSubview(fhvc.view)
     fhvc.topLayoutGuideViewController = contentViewController
-    #if swift(>=4.2)
     fhvc.didMove(toParent: contentViewController)
-    #else
-    fhvc.didMove(toParentViewController: contentViewController)
-    #endif
     fhvc.headerView.trackingScrollDidScroll()
     contentViewController.collectionView!.contentOffset =
       CGPoint(x: 0, y: -contentViewController.collectionView!.contentInset.top)
@@ -316,13 +226,11 @@ class FlexibleHeaderInjectionTopLayoutGuideTests: XCTestCase {
 
     // Then
     XCTAssertEqual(contentViewController.topLayoutGuide.length, fhvc.headerView.frame.maxY)
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       XCTAssertEqual(contentViewController.additionalSafeAreaInsets.top, 0)
       XCTAssertEqual(contentViewController.collectionView!.adjustedContentInset.top,
                      fhvc.headerView.maximumHeight + MDCDeviceTopSafeAreaInset())
     }
-    #endif
   }
 
 }
diff --git a/components/FlexibleHeader/tests/unit/FlexibleHeaderScrollViewObservationTests.swift b/components/FlexibleHeader/tests/unit/FlexibleHeaderScrollViewObservationTests.swift
index 64d595608e3..28423a467d3 100644
--- a/components/FlexibleHeader/tests/unit/FlexibleHeaderScrollViewObservationTests.swift
+++ b/components/FlexibleHeader/tests/unit/FlexibleHeaderScrollViewObservationTests.swift
@@ -43,17 +43,9 @@ class FlexibleHeaderScrollViewObservationTests: XCTestCase {
       CGSize(width: contentViewController.tableView.bounds.width,
              height: contentViewController.tableView.bounds.height * 2)
     fhvc.headerView.trackingScrollView = contentViewController.tableView
-    #if swift(>=4.2)
     contentViewController.addChild(fhvc)
-    #else
-    contentViewController.addChildViewController(fhvc)
-    #endif
     contentViewController.view.addSubview(fhvc.view)
-    #if swift(>=4.2)
     fhvc.didMove(toParent: contentViewController)
-    #else
-    fhvc.didMove(toParentViewController: contentViewController)
-    #endif
     
     // When
     let overshoot: CGFloat = 10
@@ -75,19 +67,11 @@ class FlexibleHeaderScrollViewObservationTests: XCTestCase {
              height: contentViewController.tableView.bounds.height * 2)
     fhvc.headerView.trackingScrollView = contentViewController.tableView
 
-    #if swift(>=4.2)
     contentViewController.addChild(fhvc)
-    #else
-    contentViewController.addChildViewController(fhvc)
-    #endif
 
     contentViewController.view.addSubview(fhvc.view)
 
-    #if swift(>=4.2)
     fhvc.didMove(toParent: contentViewController)
-    #else
-    fhvc.didMove(toParentViewController: contentViewController)
-    #endif
 
     // When
     let scrollAmount: CGFloat = fhvc.headerView.maximumHeight
diff --git a/components/FlexibleHeader/tests/unit/FlexibleHeaderWrappingLegacyTopLayoutGuideTests.swift b/components/FlexibleHeader/tests/unit/FlexibleHeaderWrappingLegacyTopLayoutGuideTests.swift
index 671becef1fe..79ba7f69540 100644
--- a/components/FlexibleHeader/tests/unit/FlexibleHeaderWrappingLegacyTopLayoutGuideTests.swift
+++ b/components/FlexibleHeader/tests/unit/FlexibleHeaderWrappingLegacyTopLayoutGuideTests.swift
@@ -47,11 +47,9 @@ class FlexibleHeaderWrappingLegacyTopLayoutGuideTests: XCTestCase {
 
     // Then
     XCTAssertEqual(contentViewController.topLayoutGuide.length, 0)
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       XCTAssertEqual(contentViewController.additionalSafeAreaInsets.top, 0)
     }
-    #endif
   }
 
   // MARK: Untracked table view
@@ -64,12 +62,10 @@ class FlexibleHeaderWrappingLegacyTopLayoutGuideTests: XCTestCase {
 
     // Then
     XCTAssertEqual(contentViewController.topLayoutGuide.length, 0)
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       XCTAssertEqual(contentViewController.additionalSafeAreaInsets.top, 0)
       XCTAssertEqual(contentViewController.tableView.adjustedContentInset.top, 0)
     }
-    #endif
   }
 
   // MARK: Tracked table view
@@ -84,13 +80,11 @@ class FlexibleHeaderWrappingLegacyTopLayoutGuideTests: XCTestCase {
 
     // Then
     XCTAssertEqual(contentViewController.topLayoutGuide.length, 0)
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       XCTAssertEqual(contentViewController.additionalSafeAreaInsets.top, 0)
       XCTAssertEqual(contentViewController.tableView.adjustedContentInset.top,
                      container.headerViewController.headerView.maximumHeight)
     }
-    #endif
   }
 
   // MARK: Untracked collection view
@@ -104,12 +98,10 @@ class FlexibleHeaderWrappingLegacyTopLayoutGuideTests: XCTestCase {
 
     // Then
     XCTAssertEqual(contentViewController.topLayoutGuide.length, 0)
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       XCTAssertEqual(contentViewController.additionalSafeAreaInsets.top, 0)
       XCTAssertEqual(contentViewController.collectionView!.adjustedContentInset.top, 0)
     }
-    #endif
   }
 
   // MARK: Tracked collection view view
@@ -126,13 +118,11 @@ class FlexibleHeaderWrappingLegacyTopLayoutGuideTests: XCTestCase {
 
     // Then
     XCTAssertEqual(contentViewController.topLayoutGuide.length, 0)
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       XCTAssertEqual(contentViewController.additionalSafeAreaInsets.top, 0)
       XCTAssertEqual(contentViewController.collectionView!.adjustedContentInset.top,
                      container.headerViewController.headerView.maximumHeight)
     }
-    #endif
   }
 
 }
diff --git a/components/FlexibleHeader/tests/unit/FlexibleHeaderWrappingTopLayoutGuideTests.swift b/components/FlexibleHeader/tests/unit/FlexibleHeaderWrappingTopLayoutGuideTests.swift
index 4fec05bb5fb..365eb6673bd 100644
--- a/components/FlexibleHeader/tests/unit/FlexibleHeaderWrappingTopLayoutGuideTests.swift
+++ b/components/FlexibleHeader/tests/unit/FlexibleHeaderWrappingTopLayoutGuideTests.swift
@@ -48,12 +48,10 @@ class FlexibleHeaderWrappingTopLayoutGuideTests: XCTestCase {
     XCTAssertEqual(contentViewController.view.frame, container.view.bounds)
     XCTAssertEqual(contentViewController.topLayoutGuide.length,
                    container.headerViewController.headerView.frame.maxY)
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       XCTAssertEqual(contentViewController.additionalSafeAreaInsets.top,
                      container.headerViewController.headerView.frame.maxY)
     }
-    #endif
   }
 
   func testEarlyViewLoadStillAffectsTopLayoutGuide() {
@@ -67,12 +65,10 @@ class FlexibleHeaderWrappingTopLayoutGuideTests: XCTestCase {
     XCTAssertEqual(contentViewController.view.frame, container.view.bounds)
     XCTAssertEqual(contentViewController.topLayoutGuide.length,
                    container.headerViewController.headerView.frame.maxY)
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       XCTAssertEqual(contentViewController.additionalSafeAreaInsets.top,
                      container.headerViewController.headerView.frame.maxY)
     }
-    #endif
   }
 
   // MARK: Untracked table view
@@ -88,13 +84,11 @@ class FlexibleHeaderWrappingTopLayoutGuideTests: XCTestCase {
     XCTAssertEqual(contentViewController.view.frame, container.view.bounds)
     XCTAssertEqual(contentViewController.topLayoutGuide.length,
                    container.headerViewController.headerView.frame.maxY)
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       XCTAssertEqual(contentViewController.additionalSafeAreaInsets.top,
                      container.headerViewController.headerView.frame.maxY)
       XCTAssertEqual(contentViewController.tableView.adjustedContentInset.top, 0)
     }
-    #endif
   }
 
   // MARK: Tracked table view
@@ -110,13 +104,11 @@ class FlexibleHeaderWrappingTopLayoutGuideTests: XCTestCase {
     // Then
     XCTAssertEqual(contentViewController.topLayoutGuide.length,
                    container.headerViewController.headerView.frame.maxY)
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       XCTAssertEqual(contentViewController.additionalSafeAreaInsets.top, 0)
       XCTAssertEqual(contentViewController.tableView.adjustedContentInset.top,
                      container.headerViewController.headerView.maximumHeight)
     }
-    #endif
   }
 
   // MARK: Untracked collection view
@@ -133,13 +125,11 @@ class FlexibleHeaderWrappingTopLayoutGuideTests: XCTestCase {
     XCTAssertEqual(contentViewController.view.frame, container.view.bounds)
     XCTAssertEqual(contentViewController.topLayoutGuide.length,
                    container.headerViewController.headerView.frame.maxY)
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       XCTAssertEqual(contentViewController.additionalSafeAreaInsets.top,
                      container.headerViewController.headerView.frame.maxY)
       XCTAssertEqual(contentViewController.collectionView!.adjustedContentInset.top, 0)
     }
-    #endif
   }
 
   // MARK: Tracked collection view view
@@ -159,13 +149,11 @@ class FlexibleHeaderWrappingTopLayoutGuideTests: XCTestCase {
     XCTAssertEqual(contentViewController.view.frame, container.view.bounds)
     XCTAssertEqual(contentViewController.topLayoutGuide.length,
                    container.headerViewController.headerView.frame.maxY)
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       XCTAssertEqual(contentViewController.additionalSafeAreaInsets.top, 0)
       XCTAssertEqual(contentViewController.collectionView!.adjustedContentInset.top,
                      container.headerViewController.headerView.maximumHeight)
     }
-    #endif
   }
 
 }
diff --git a/components/LibraryInfo/BUILD b/components/LibraryInfo/BUILD
index ea434f0f09c..8f3a7a7fec5 100644
--- a/components/LibraryInfo/BUILD
+++ b/components/LibraryInfo/BUILD
@@ -35,7 +35,7 @@ swift_library(
     srcs = glob(["tests/unit/*.swift"]),
     copts = [
         "-swift-version",
-        "3",
+        "4.2",
     ],
     visibility = ["//visibility:private"],
     deps = [":LibraryInfo"],
diff --git a/components/List/examples/BaseCellExample.swift b/components/List/examples/BaseCellExample.swift
index e45e55ff59f..9eef3617f76 100644
--- a/components/List/examples/BaseCellExample.swift
+++ b/components/List/examples/BaseCellExample.swift
@@ -64,14 +64,12 @@ class BaseCellExample : UIViewController {
     var width = view.bounds.size.width
     var height = view.bounds.size.height
 
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       originX += view.safeAreaInsets.left
       originY += view.safeAreaInsets.top
       width -= (view.safeAreaInsets.left + view.safeAreaInsets.right)
       height -= (view.safeAreaInsets.top + view.safeAreaInsets.bottom)
     }
-    #endif
 
     let frame = CGRect(x: originX, y: originY, width: width, height: height);
     collectionView.frame = frame
diff --git a/components/MaskedTransition/BUILD b/components/MaskedTransition/BUILD
index 1fa040c63f2..a99a992bb5e 100644
--- a/components/MaskedTransition/BUILD
+++ b/components/MaskedTransition/BUILD
@@ -67,7 +67,7 @@ swift_library(
     srcs = native.glob(["examples/*.swift"]),
     copts = [
         "-swift-version",
-        "3",
+        "4.2",
     ],
     deps = [
         ":MaskedTransition",
diff --git a/components/MaskedTransition/examples/MaskedTransitionTypicalUse.swift b/components/MaskedTransition/examples/MaskedTransitionTypicalUse.swift
index 518d15f7a7c..dc859ee425d 100644
--- a/components/MaskedTransition/examples/MaskedTransitionTypicalUse.swift
+++ b/components/MaskedTransition/examples/MaskedTransitionTypicalUse.swift
@@ -23,7 +23,7 @@ open class MaskedTransitionTypicalUseSwiftExample: UIViewController {
     let name: String
     let viewControllerType: UIViewController.Type
     let calculateFrame: ((UIPresentationController) -> CGRect)?
-    let autoresizingMask: UIViewAutoresizing
+    let autoresizingMask: UIView.AutoresizingMask
     let useSafeAreaInsets: Bool
   }
   var targets: [TargetInfo] = []
@@ -118,7 +118,7 @@ open class MaskedTransitionTypicalUseSwiftExample: UIViewController {
   }
 
   var transitionController: MDCMaskedTransitionController? = nil
-  func didTapFab(fab: UIView) {
+  @objc func didTapFab(fab: UIView) {
     guard let indexPathForSelectedRow = tableView.indexPathForSelectedRow else { return }
     let target = targets[indexPathForSelectedRow.row]
     let vc = target.viewControllerType.init()
@@ -169,7 +169,7 @@ private class ToolbarViewController: UIViewController {
     view.addSubview(toolbar)
   }
 
-  func didTap() {
+  @objc func didTap() {
     dismiss(animated: true)
   }
 }
@@ -238,7 +238,7 @@ private class ModalViewController: UIViewController {
                        constant: bottomOffset).isActive = true
   }
   
-  func didTap() {
+  @objc func didTap() {
     dismiss(animated: true)
   }
 }
diff --git a/components/NavigationBar/BUILD b/components/NavigationBar/BUILD
index 42ddefb5699..ef431736ab4 100644
--- a/components/NavigationBar/BUILD
+++ b/components/NavigationBar/BUILD
@@ -108,7 +108,7 @@ swift_library(
     srcs = native.glob(["tests/unit/*.swift"]),
     copts = [
         "-swift-version",
-        "3",
+        "4.2",
     ],
     visibility = ["//visibility:private"],
     deps = [
diff --git a/components/NavigationBar/examples/NavigationBarTypicalUseExample.swift b/components/NavigationBar/examples/NavigationBarTypicalUseExample.swift
index 96863995815..e3f0f7384a6 100644
--- a/components/NavigationBar/examples/NavigationBarTypicalUseExample.swift
+++ b/components/NavigationBar/examples/NavigationBarTypicalUseExample.swift
@@ -40,19 +40,9 @@ open class NavigationBarTypicalUseSwiftExample: UIViewController {
 
     navBar.translatesAutoresizingMaskIntoConstraints = false
 
-    #if swift(>=3.2)
-      if #available(iOS 11.0, *) {
-        self.view.safeAreaLayoutGuide.topAnchor.constraint(equalTo: self.navBar.topAnchor).isActive = true
-      } else {
-        NSLayoutConstraint(item: self.topLayoutGuide,
-                           attribute: .bottom,
-                           relatedBy: .equal,
-                           toItem: self.navBar,
-                           attribute: .top,
-                           multiplier: 1,
-                           constant: 0).isActive = true
-      }
-    #else
+    if #available(iOS 11.0, *) {
+      self.view.safeAreaLayoutGuide.topAnchor.constraint(equalTo: self.navBar.topAnchor).isActive = true
+    } else {
       NSLayoutConstraint(item: self.topLayoutGuide,
                          attribute: .bottom,
                          relatedBy: .equal,
@@ -60,7 +50,7 @@ open class NavigationBarTypicalUseSwiftExample: UIViewController {
                          attribute: .top,
                          multiplier: 1,
                          constant: 0).isActive = true
-    #endif
+    }
 
     let viewBindings = ["navBar": navBar]
 
@@ -140,14 +130,14 @@ class ExampleInstructionsViewNavigationBarTypicalUseSwift: UIView {
     style.alignment = .center
     style.lineBreakMode = .byWordWrapping
     let instructionsDictionary1 = [
-      NSFontAttributeName : UIFont.preferredFont(forTextStyle: .headline),
-      NSForegroundColorAttributeName : MDCPalette.grey.tint600.withAlphaComponent(0.87),
-      NSParagraphStyleAttributeName : style
+      NSAttributedString.Key.font : UIFont.preferredFont(forTextStyle: .headline),
+      NSAttributedString.Key.foregroundColor : MDCPalette.grey.tint600.withAlphaComponent(0.87),
+      NSAttributedString.Key.paragraphStyle : style
     ]
     let instructionsDictionary2 = [
-      NSFontAttributeName : UIFont.preferredFont(forTextStyle: .subheadline),
-      NSForegroundColorAttributeName : MDCPalette.grey.tint600.withAlphaComponent(0.87),
-      NSParagraphStyleAttributeName : style
+      NSAttributedString.Key.font : UIFont.preferredFont(forTextStyle: .subheadline),
+      NSAttributedString.Key.foregroundColor : MDCPalette.grey.tint600.withAlphaComponent(0.87),
+      NSAttributedString.Key.paragraphStyle : style
     ]
     let instructionText = "SWIPE RIGHT\n\n\nfrom left edge to go back\n\n\n\n\n"
     let instructionsAttributedString = NSMutableAttributedString(string: instructionText)
diff --git a/components/NavigationBar/tests/unit/NavigationBarAccessibilityMutatorTestColorTest.swift b/components/NavigationBar/tests/unit/NavigationBarAccessibilityMutatorTestColorTest.swift
index 26a095fb01f..1d6cbbbff6b 100644
--- a/components/NavigationBar/tests/unit/NavigationBarAccessibilityMutatorTestColorTest.swift
+++ b/components/NavigationBar/tests/unit/NavigationBarAccessibilityMutatorTestColorTest.swift
@@ -46,7 +46,7 @@ class NavigationBarAccessibilityMutatorTestColorTest: XCTestCase {
     mutator.mutate(navBar)
 
     // Then
-    let fontColor = navBar.titleTextAttributes![NSForegroundColorAttributeName] as! UIColor
+    let fontColor = navBar.titleTextAttributes![NSAttributedString.Key.foregroundColor] as! UIColor
     let tintColor = navBar.tintColor
     let accessibleColor = MDFTextAccessibility.textColor(onBackgroundColor: UIColor.black,
                                                          targetTextAlpha: 1.0,
@@ -64,7 +64,7 @@ class NavigationBarAccessibilityMutatorTestColorTest: XCTestCase {
     mutator.mutate(navBar)
 
     // Then
-    let fontColor = navBar.titleTextAttributes![NSForegroundColorAttributeName] as! UIColor
+    let fontColor = navBar.titleTextAttributes![NSAttributedString.Key.foregroundColor] as! UIColor
     let tintColor = navBar.tintColor
     let accessibleColor = MDFTextAccessibility.textColor(onBackgroundColor: UIColor.white,
                                                          targetTextAlpha: 1.0,
@@ -75,14 +75,16 @@ class NavigationBarAccessibilityMutatorTestColorTest: XCTestCase {
 
   func testNoBackgroundColor() {
     // Given no background color set
-    let fontColorBefore = navBar.titleTextAttributes?[NSForegroundColorAttributeName] as? UIColor
+    let fontColorBefore = navBar.titleTextAttributes?[NSAttributedString.Key.foregroundColor]
+      as? UIColor
     let tintColorBefore = navBar.tintColor
 
     // When
     mutator.mutate(navBar)
 
     // Then
-    let fontColorAfter = navBar.titleTextAttributes?[NSForegroundColorAttributeName] as? UIColor
+    let fontColorAfter = navBar.titleTextAttributes?[NSAttributedString.Key.foregroundColor]
+      as? UIColor
     let tintColorAfter = navBar.tintColor
     XCTAssertEqual(fontColorBefore, fontColorAfter)
     XCTAssertEqual(tintColorBefore, tintColorAfter)
diff --git a/components/NavigationDrawer/examples/BottomDrawerWithChangingContentSize.swift b/components/NavigationDrawer/examples/BottomDrawerWithChangingContentSize.swift
index d4d0fbe4a9a..27449491ff5 100644
--- a/components/NavigationDrawer/examples/BottomDrawerWithChangingContentSize.swift
+++ b/components/NavigationDrawer/examples/BottomDrawerWithChangingContentSize.swift
@@ -143,7 +143,7 @@ UICollectionViewDelegate, UICollectionViewDataSource {
     return 1
   }
 
-  func didTap(gestureRecognizer : UITapGestureRecognizer) {
+  @objc func didTap(gestureRecognizer : UITapGestureRecognizer) {
     longList = !longList
     collectionView.reloadData()
     self.preferredContentSize = CGSize(width: self.view.bounds.width,
diff --git a/components/NavigationDrawer/examples/BottomDrawerWithHeaderExample.swift b/components/NavigationDrawer/examples/BottomDrawerWithHeaderExample.swift
index 6c52a95dfa1..977b76787e8 100644
--- a/components/NavigationDrawer/examples/BottomDrawerWithHeaderExample.swift
+++ b/components/NavigationDrawer/examples/BottomDrawerWithHeaderExample.swift
@@ -86,7 +86,7 @@ class BottomDrawerWithHeaderExample: UIViewController, MDCBottomDrawerViewContro
 
 extension BottomDrawerWithHeaderExample {
 
-  class func catalogMetadata() -> [String: Any] {
+  @objc class func catalogMetadata() -> [String: Any] {
     return [
       "breadcrumbs": ["Navigation Drawer", "Bottom Drawer"],
       "primaryDemo": false,
diff --git a/components/PageControl/examples/PageControlTypicalUseExample.swift b/components/PageControl/examples/PageControlTypicalUseExample.swift
index d769c9ed3bb..2c7b13047ec 100644
--- a/components/PageControl/examples/PageControlTypicalUseExample.swift
+++ b/components/PageControl/examples/PageControlTypicalUseExample.swift
@@ -86,11 +86,9 @@ class PageControlSwiftExampleViewController: UIViewController, UIScrollViewDeleg
     scrollView.contentOffset = offset
 
     var edgeInsets = UIEdgeInsets.zero;
-    #if swift(>=3.2)
-      if #available(iOS 11, *) {
-        edgeInsets = self.view.safeAreaInsets
-      }
-    #endif
+    if #available(iOS 11, *) {
+      edgeInsets = self.view.safeAreaInsets
+    }
     let pageControlSize = pageControl.sizeThatFits(view.bounds.size)
     let yOffset = self.view.bounds.height - pageControlSize.height - 8 - edgeInsets.bottom;
     pageControl.frame =
diff --git a/components/Palettes/BUILD b/components/Palettes/BUILD
index 3e975d7b2ca..6021ae230a7 100644
--- a/components/Palettes/BUILD
+++ b/components/Palettes/BUILD
@@ -32,7 +32,7 @@ swift_library(
     srcs = glob(["tests/unit/*.swift"]),
     copts = [
         "-swift-version",
-        "3",
+        "4.2",
     ],
     visibility = ["//visibility:private"],
     deps = [":Palettes"],
diff --git a/components/Palettes/examples/supplemental/PalettesExampleViewController.swift b/components/Palettes/examples/supplemental/PalettesExampleViewController.swift
index 156960aa04e..c592853ea50 100644
--- a/components/Palettes/examples/supplemental/PalettesExampleViewController.swift
+++ b/components/Palettes/examples/supplemental/PalettesExampleViewController.swift
@@ -60,7 +60,7 @@ class PalettesExampleViewController: UITableViewController {
   override func viewDidLoad() {
     super.viewDidLoad()
     self.tableView.separatorStyle = .none
-    self.tableView.rowHeight = UITableViewAutomaticDimension
+    self.tableView.rowHeight = UITableView.automaticDimension
     self.tableView.estimatedRowHeight = 50
   }
 
@@ -109,7 +109,7 @@ class PalettesExampleViewController: UITableViewController {
     self.init(style: .grouped)
   }
 
-  override init(style: UITableViewStyle) {
+  override init(style: UITableView.Style) {
     super.init(style: style)
   }
 
diff --git a/components/Ripple/examples/CardCellsWithRippleExample.swift b/components/Ripple/examples/CardCellsWithRippleExample.swift
index f30e34572a9..dc242a9c496 100644
--- a/components/Ripple/examples/CardCellsWithRippleExample.swift
+++ b/components/Ripple/examples/CardCellsWithRippleExample.swift
@@ -76,21 +76,17 @@ class CardCellsWithRippleExample: UIViewController,
       collectionView.addGestureRecognizer(longPressGesture)
     }
 
-    #if swift(>=3.2)
-      if #available(iOS 11, *) {
-        let guide = view.safeAreaLayoutGuide
-        NSLayoutConstraint.activate([
-          collectionView.leftAnchor.constraint(equalTo: guide.leftAnchor),
-          collectionView.rightAnchor.constraint(equalTo: guide.rightAnchor),
-          collectionView.topAnchor.constraint(equalTo: view.topAnchor),
-          collectionView.bottomAnchor.constraint(equalTo: guide.bottomAnchor)])
-        collectionView.contentInsetAdjustmentBehavior = .always
-      } else {
-        preiOS11Constraints()
-      }
-    #else
+    if #available(iOS 11, *) {
+      let guide = view.safeAreaLayoutGuide
+      NSLayoutConstraint.activate([
+        collectionView.leftAnchor.constraint(equalTo: guide.leftAnchor),
+        collectionView.rightAnchor.constraint(equalTo: guide.rightAnchor),
+        collectionView.topAnchor.constraint(equalTo: view.topAnchor),
+        collectionView.bottomAnchor.constraint(equalTo: guide.bottomAnchor)])
+      collectionView.contentInsetAdjustmentBehavior = .always
+    } else {
       preiOS11Constraints()
-    #endif
+    }
 
     self.updateTitle()
   }
@@ -117,7 +113,7 @@ class CardCellsWithRippleExample: UIViewController,
     }
   }
 
-  func toggleModes() {
+  @objc func toggleModes() {
     switch toggle {
     case .edit:
       toggle = .reorder
diff --git a/components/ShadowElevations/examples/ShadowElevationsTypicalUseExample.swift b/components/ShadowElevations/examples/ShadowElevationsTypicalUseExample.swift
index ae5a5a8d1e3..3bcd7f0b041 100644
--- a/components/ShadowElevations/examples/ShadowElevationsTypicalUseExample.swift
+++ b/components/ShadowElevations/examples/ShadowElevationsTypicalUseExample.swift
@@ -47,12 +47,13 @@ class ShadowElevationsTypicalUseExample: UIViewController {
     super.init(nibName: nil, bundle: nil)
 
     self.title = "Shadow Elevations (Swift)"
-    self.addChildViewController(appBarViewController)
+    self.addChild(appBarViewController)
 
     let color = UIColor(white: 0.2, alpha:1)
     appBarViewController.headerView.backgroundColor = color
     appBarViewController.navigationBar.tintColor = .white
-    appBarViewController.navigationBar.titleTextAttributes = [NSForegroundColorAttributeName : UIColor.white]
+    appBarViewController.navigationBar.titleTextAttributes =
+      [NSAttributedString.Key.foregroundColor : UIColor.white]
 
     let paperDim = CGFloat(200)
     paper.frame =
@@ -70,7 +71,7 @@ class ShadowElevationsTypicalUseExample: UIViewController {
     super.viewDidLoad()
 
     view.addSubview(appBarViewController.view)
-    appBarViewController.didMove(toParentViewController: self)
+    appBarViewController.didMove(toParent: self)
   }
 
   override func viewWillAppear(_ animated: Bool) {
diff --git a/components/Snackbar/BUILD b/components/Snackbar/BUILD
index fa5d20f24dc..66e847d469e 100644
--- a/components/Snackbar/BUILD
+++ b/components/Snackbar/BUILD
@@ -111,7 +111,7 @@ swift_library(
     srcs = glob(["tests/unit/*.swift"]),
     copts = [
         "-swift-version",
-        "3",
+        "4.2",
     ],
     visibility = ["//visibility:private"],
     deps = [
diff --git a/components/Tabs/examples/supplemental/TabBarIconExampleSupplemental.swift b/components/Tabs/examples/supplemental/TabBarIconExampleSupplemental.swift
index 24619559e40..8a21235cb9d 100644
--- a/components/Tabs/examples/supplemental/TabBarIconExampleSupplemental.swift
+++ b/components/Tabs/examples/supplemental/TabBarIconExampleSupplemental.swift
@@ -61,7 +61,7 @@ extension TabBarIconSwiftExample {
   func setupAppBar() -> MDCAppBarViewController {
     let appBarViewController = MDCAppBarViewController()
 
-    self.addChildViewController(appBarViewController)
+    self.addChild(appBarViewController)
     appBarViewController.headerView.minMaxHeightIncludesSafeArea = false
     appBarViewController.headerView.minimumHeight = 56 + 72
     appBarViewController.headerView.tintColor = MDCPalette.blue.tint500
@@ -77,7 +77,7 @@ extension TabBarIconSwiftExample {
     view.backgroundColor = UIColor.white
 
     view.addSubview(appBarViewController.view)
-    appBarViewController.didMove(toParentViewController: self)
+    appBarViewController.didMove(toParent: self)
 
     let badgeIncrementItem = UIBarButtonItem(title: "Add",
                                              style: .plain,
@@ -233,7 +233,7 @@ extension TabBarIconSwiftExample {
 }
 
 extension TabBarIconSwiftExample {
-  override var childViewControllerForStatusBarStyle: UIViewController? {
+  override var childForStatusBarStyle: UIViewController? {
     return appBarViewController
   }
 
diff --git a/components/Tabs/examples/supplemental/TabBarIndicatorTemplateExampleSupplemental.swift b/components/Tabs/examples/supplemental/TabBarIndicatorTemplateExampleSupplemental.swift
index 78bc89606be..8880e6bc338 100644
--- a/components/Tabs/examples/supplemental/TabBarIndicatorTemplateExampleSupplemental.swift
+++ b/components/Tabs/examples/supplemental/TabBarIndicatorTemplateExampleSupplemental.swift
@@ -44,7 +44,7 @@ extension TabBarIndicatorTemplateExample {
   func makeAppBar() -> MDCAppBarViewController {
     let appBarViewController = MDCAppBarViewController()
 
-    self.addChildViewController(appBarViewController)
+    self.addChild(appBarViewController)
 
     // Give the tab bar enough height to accomodate all possible item appearances.
     appBarViewController.headerView.minMaxHeightIncludesSafeArea = false
@@ -58,7 +58,7 @@ extension TabBarIndicatorTemplateExample {
   func setupExampleViews() {
     view.backgroundColor = UIColor.white
     view.addSubview(appBarViewController.view)
-    appBarViewController.didMove(toParentViewController: self)
+    appBarViewController.didMove(toParent: self)
 
     // Set up buttons
     alignmentButton.translatesAutoresizingMaskIntoConstraints = false
@@ -68,15 +68,11 @@ extension TabBarIndicatorTemplateExample {
 
     // Buttons are laid out relative to the safe area, if available.
     let alignmentGuide: Any
-    #if swift(>=3.2)
-      if #available(iOS 11.0, *) {
-        alignmentGuide = view.safeAreaLayoutGuide
-      } else {
-        alignmentGuide = view
-      }
-    #else
+    if #available(iOS 11.0, *) {
+      alignmentGuide = view.safeAreaLayoutGuide
+    } else {
       alignmentGuide = view
-    #endif
+    }
 
     NSLayoutConstraint.activate([
       // Center alignment button
@@ -117,7 +113,7 @@ extension TabBarIndicatorTemplateExample {
 }
 
 extension TabBarIndicatorTemplateExample {
-  override var childViewControllerForStatusBarStyle: UIViewController? {
+  override var childForStatusBarStyle: UIViewController? {
     return appBarViewController
   }
 }
diff --git a/components/TextFields/BUILD b/components/TextFields/BUILD
index 1b5aca21c67..8de3b677224 100644
--- a/components/TextFields/BUILD
+++ b/components/TextFields/BUILD
@@ -127,7 +127,7 @@ swift_library(
     srcs = glob(["examples/experimental/*.swift"]),
     copts = [
         "-swift-version",
-        "3",
+        "4.2",
     ],
     deps = [":ExperimentalExampleSource"],
 )
@@ -196,7 +196,7 @@ swift_library(
     ]),
     copts = [
         "-swift-version",
-        "3",
+        "4.2",
     ],
     visibility = ["//visibility:private"],
     deps = [
diff --git a/components/TextFields/examples/TextFieldFilledExample.swift b/components/TextFields/examples/TextFieldFilledExample.swift
index b5dcb9598a0..3db844e04c4 100644
--- a/components/TextFields/examples/TextFieldFilledExample.swift
+++ b/components/TextFields/examples/TextFieldFilledExample.swift
@@ -178,15 +178,11 @@ final class TextFieldFilledSwiftExample: UIViewController {
     scrollView.addSubview(message)
     let messageController = MDCTextInputControllerFilled(textInput: message)
     message.textView?.delegate = self
-    #if swift(>=3.2)
-      message.text = """
-      This is where you could put a multi-line message like an email.
-
-      It can even handle new lines.
-      """
-    #else
-      message.text = "This is where you could put a multi-line message like an email.\n\nIt can even handle new lines."
-    #endif
+    message.text = """
+    This is where you could put a multi-line message like an email.
+
+    It can even handle new lines.
+    """
     messageController.placeholderText = "Message"
     allTextFieldControllers.append(messageController)
 
@@ -228,39 +224,22 @@ final class TextFieldFilledSwiftExample: UIViewController {
                                                   options: [],
                                                   metrics: nil,
                                                   views: views)
-    #if swift(>=3.2)
-      if #available(iOS 11.0, *) {
-        constraints += [NSLayoutConstraint(item: name,
-                                           attribute: .top,
-                                           relatedBy: .equal,
-                                           toItem: scrollView.contentLayoutGuide,
-                                           attribute: .top,
-                                           multiplier: 1,
-                                           constant: 20),
-                        NSLayoutConstraint(item: message,
-                                           attribute: .bottom,
-                                           relatedBy: .equal,
-                                           toItem: scrollView.contentLayoutGuide,
-                                           attribute: .bottomMargin,
-                                           multiplier: 1,
-                                           constant: -20)]
-      } else {
-        constraints += [NSLayoutConstraint(item: name,
-                                           attribute: .top,
-                                           relatedBy: .equal,
-                                           toItem: scrollView,
-                                           attribute: .top,
-                                           multiplier: 1,
-                                           constant: 20),
-                        NSLayoutConstraint(item: message,
-                                           attribute: .bottom,
-                                           relatedBy: .equal,
-                                           toItem: scrollView,
-                                           attribute: .bottomMargin,
-                                           multiplier: 1,
-                                           constant: -20)]
-      }
-    #else
+    if #available(iOS 11.0, *) {
+      constraints += [NSLayoutConstraint(item: name,
+                                         attribute: .top,
+                                         relatedBy: .equal,
+                                         toItem: scrollView.contentLayoutGuide,
+                                         attribute: .top,
+                                         multiplier: 1,
+                                         constant: 20),
+                      NSLayoutConstraint(item: message,
+                                         attribute: .bottom,
+                                         relatedBy: .equal,
+                                         toItem: scrollView.contentLayoutGuide,
+                                         attribute: .bottomMargin,
+                                         multiplier: 1,
+                                         constant: -20)]
+    } else {
       constraints += [NSLayoutConstraint(item: name,
                                          attribute: .top,
                                          relatedBy: .equal,
@@ -275,7 +254,7 @@ final class TextFieldFilledSwiftExample: UIViewController {
                                          attribute: .bottomMargin,
                                          multiplier: 1,
                                          constant: -20)]
-      #endif
+    }
 
     let stateZipViews = [ "state": state, "zip": zip ]
     constraints += NSLayoutConstraint.constraints(withVisualFormat: "H:|[state(80)]-[zip]|",
@@ -361,14 +340,15 @@ extension TextFieldFilledSwiftExample: UITextFieldDelegate {
 
     if textField == state {
       if let range = fullString.rangeOfCharacter(from: CharacterSet.letters.inverted),
-        fullString[range].characterCount > 0 {
+        String(fullString[range]).characterCount > 0 {
         stateController.setErrorText("Error: State can only contain letters",
                                      errorAccessibilityValue: nil)
       } else {
         stateController.setErrorText(nil, errorAccessibilityValue: nil)
       }
-    } else if textField == zip {      if let range = fullString.rangeOfCharacter(from: CharacterSet.letters),
-        fullString[range].characterCount > 0 {
+    } else if textField == zip {
+      if let range = fullString.rangeOfCharacter(from: CharacterSet.letters),
+        String(fullString[range]).characterCount > 0 {
         zipController.setErrorText("Error: Zip can only contain numbers",
                                    errorAccessibilityValue: nil)
       } else if fullString.characterCount > 5 {
@@ -379,7 +359,7 @@ extension TextFieldFilledSwiftExample: UITextFieldDelegate {
       }
     } else if textField == city {
       if let range = fullString.rangeOfCharacter(from: CharacterSet.decimalDigits),
-        fullString[range].characterCount > 0 {
+        String(fullString[range]).characterCount > 0 {
         cityController.setErrorText("Error: City can only contain letters",
                                     errorAccessibilityValue: nil)
       } else {
@@ -416,22 +396,22 @@ extension TextFieldFilledSwiftExample {
     notificationCenter.addObserver(
       self,
       selector: #selector(keyboardWillShow(notif:)),
-      name: .UIKeyboardWillShow,
+      name: UIResponder.keyboardWillShowNotification,
       object: nil)
     notificationCenter.addObserver(
       self,
       selector: #selector(keyboardWillShow(notif:)),
-      name: .UIKeyboardWillChangeFrame,
+      name: UIResponder.keyboardWillChangeFrameNotification,
       object: nil)
     notificationCenter.addObserver(
       self,
       selector: #selector(keyboardWillHide(notif:)),
-      name: .UIKeyboardWillHide,
+      name: UIResponder.keyboardWillHideNotification,
       object: nil)
   }
 
   @objc func keyboardWillShow(notif: Notification) {
-    guard let frame = notif.userInfo?[UIKeyboardFrameEndUserInfoKey] as? CGRect else {
+    guard let frame = notif.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? CGRect else {
       return
     }
     scrollView.contentInset = UIEdgeInsets(top: 0.0,
diff --git a/components/TextFields/examples/TextFieldLegacyExample.swift b/components/TextFields/examples/TextFieldLegacyExample.swift
index 80ecb8000de..a597579fe93 100644
--- a/components/TextFields/examples/TextFieldLegacyExample.swift
+++ b/components/TextFields/examples/TextFieldLegacyExample.swift
@@ -149,15 +149,11 @@ final class TextFieldLegacySwiftExample: UIViewController {
 
     scrollView.addSubview(message)
     let messageController = MDCTextInputControllerLegacyDefault(textInput: message)
-    #if swift(>=3.2)
-      message.text = """
-      This is where you could put a multi-line message like an email.
-
-      It can even handle new lines.
-      """
-    #else
-      message.text = "This is where you could put a multi-line message like an email. It can even handle new lines./n"
-    #endif
+    message.text = """
+    This is where you could put a multi-line message like an email.
+
+    It can even handle new lines.
+    """
     message.textView?.delegate = self
     messageController.placeholderText = "Message"
     allTextFieldControllers.append(messageController)
@@ -199,8 +195,7 @@ final class TextFieldLegacySwiftExample: UIViewController {
                                                   options: [],
                                                   metrics: nil,
                                                   views: views)
-    #if swift(>=3.2)
-      if #available(iOS 11.0, *) {
+    if #available(iOS 11.0, *) {
       constraints += [NSLayoutConstraint(item: name,
                                          attribute: .top,
                                          relatedBy: .equal,
@@ -231,23 +226,6 @@ final class TextFieldLegacySwiftExample: UIViewController {
                                          multiplier: 1,
                                          constant: -20)]
     }
-      #else
-      constraints += [NSLayoutConstraint(item: name,
-                                         attribute: .top,
-                                         relatedBy: .equal,
-                                         toItem: scrollView,
-                                         attribute: .top,
-                                         multiplier: 1,
-                                         constant: 20),
-                      NSLayoutConstraint(item: message,
-                                         attribute: .bottom,
-                                         relatedBy: .equal,
-                                         toItem: scrollView,
-                                         attribute: .bottomMargin,
-                                         multiplier: 1,
-                                         constant: -20)]
-
-      #endif
     let stateZipViews = [ "state": state, "zip": zip ]
     constraints += NSLayoutConstraint.constraints(withVisualFormat: "H:|[state(80)]-[zip]|",
                                                   options: [.alignAllTop],
@@ -328,7 +306,7 @@ extension TextFieldLegacySwiftExample: UITextFieldDelegate {
 
     if textField == zip {
       if let range = fullString.rangeOfCharacter(from: CharacterSet.letters),
-        fullString[range].characterCount > 0 {
+        String(fullString[range]).characterCount > 0 {
         zipController.setErrorText("Error: Zip can only contain numbers",
                                    errorAccessibilityValue: nil)
       } else if fullString.characterCount > 5 {
@@ -339,7 +317,7 @@ extension TextFieldLegacySwiftExample: UITextFieldDelegate {
       }
     } else if textField == city {
       if let range = fullString.rangeOfCharacter(from: CharacterSet.decimalDigits),
-        fullString[range].characterCount > 0 {
+        String(fullString[range]).characterCount > 0 {
         cityController.setErrorText("Error: City can only contain letters",
                                     errorAccessibilityValue: nil)
       } else {
@@ -376,22 +354,22 @@ extension TextFieldLegacySwiftExample {
     notificationCenter.addObserver(
       self,
       selector: #selector(keyboardWillShow(notif:)),
-      name: .UIKeyboardWillShow,
+      name: UIResponder.keyboardWillShowNotification,
       object: nil)
     notificationCenter.addObserver(
       self,
       selector: #selector(keyboardWillShow(notif:)),
-      name: .UIKeyboardWillChangeFrame,
+      name: UIResponder.keyboardWillChangeFrameNotification,
       object: nil)
     notificationCenter.addObserver(
       self,
       selector: #selector(keyboardWillHide(notif:)),
-      name: .UIKeyboardWillHide,
+      name: UIResponder.keyboardWillHideNotification,
       object: nil)
   }
 
   @objc func keyboardWillShow(notif: Notification) {
-    guard let frame = notif.userInfo?[UIKeyboardFrameEndUserInfoKey] as? CGRect else {
+    guard let frame = notif.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? CGRect else {
       return
     }
     scrollView.contentInset = UIEdgeInsets(top: 0.0,
diff --git a/components/TextFields/examples/TextFieldManualLayoutLegacyExample.swift b/components/TextFields/examples/TextFieldManualLayoutLegacyExample.swift
index e14cbcde4ad..8ad428d1744 100644
--- a/components/TextFields/examples/TextFieldManualLayoutLegacyExample.swift
+++ b/components/TextFields/examples/TextFieldManualLayoutLegacyExample.swift
@@ -256,7 +256,7 @@ extension TextFieldManualLayoutLegacySwiftExample: UITextFieldDelegate {
 
     if textField == zip {
       if let range = fullString.rangeOfCharacter(from: CharacterSet.letters),
-        fullString[range].characterCount > 0 {
+        String(fullString[range]).characterCount > 0 {
         zipController.setErrorText("Error: Zip can only contain numbers",
                                    errorAccessibilityValue: nil)
       } else if fullString.characterCount > 5 {
@@ -267,7 +267,7 @@ extension TextFieldManualLayoutLegacySwiftExample: UITextFieldDelegate {
       }
     } else if textField == city {
       if let range = fullString.rangeOfCharacter(from: CharacterSet.decimalDigits),
-        fullString[range].characterCount > 0 {
+        String(fullString[range]).characterCount > 0 {
         cityController.setErrorText("Error: City can only contain letters",
                                     errorAccessibilityValue: nil)
       } else {
@@ -298,22 +298,22 @@ extension TextFieldManualLayoutLegacySwiftExample {
     notificationCenter.addObserver(
       self,
       selector: #selector(keyboardWillShow(notif:)),
-      name: .UIKeyboardWillShow,
+      name: UIResponder.keyboardWillShowNotification,
       object: nil)
     notificationCenter.addObserver(
       self,
       selector: #selector(keyboardWillShow(notif:)),
-      name: .UIKeyboardWillChangeFrame,
+      name: UIResponder.keyboardWillChangeFrameNotification,
       object: nil)
     notificationCenter.addObserver(
       self,
       selector: #selector(keyboardWillHide(notif:)),
-      name: .UIKeyboardWillHide,
+      name: UIResponder.keyboardWillHideNotification,
       object: nil)
   }
 
   @objc func keyboardWillShow(notif: Notification) {
-    guard let frame = notif.userInfo?[UIKeyboardFrameEndUserInfoKey] as? CGRect else {
+    guard let frame = notif.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? CGRect else {
       return
     }
     scrollView.contentInset = UIEdgeInsets(top: 0.0,
diff --git a/components/TextFields/examples/TextFieldOutlinedExample.swift b/components/TextFields/examples/TextFieldOutlinedExample.swift
index c4b89b9b9d2..0b2716ad5d9 100644
--- a/components/TextFields/examples/TextFieldOutlinedExample.swift
+++ b/components/TextFields/examples/TextFieldOutlinedExample.swift
@@ -167,15 +167,11 @@ final class TextFieldOutlinedSwiftExample: UIViewController {
     scrollView.addSubview(message)
     let messageController = MDCTextInputControllerOutlinedTextArea(textInput: message)
     message.textView?.delegate = self
-    #if swift(>=3.2)
-      message.text = """
-      This is where you could put a multi-line message like an email.
-
-      It can even handle new lines.
-      """
-    #else
-      message.text = "This is where you could put a multi-line message like an email. It can even handle new lines./n"
-    #endif
+    message.text = """
+    This is where you could put a multi-line message like an email.
+
+    It can even handle new lines.
+    """
     messageController.placeholderText = "Message"
     allTextFieldControllers.append(messageController)
 
@@ -220,39 +216,22 @@ final class TextFieldOutlinedSwiftExample: UIViewController {
                                                   metrics: nil,
                                                   views: views)
 
-    #if swift(>=3.2)
-      if #available(iOS 11.0, *) {
-         constraints += [NSLayoutConstraint(item: name,
-                                            attribute: .top,
-                                            relatedBy: .equal,
-                                            toItem: scrollView.contentLayoutGuide,
-                                            attribute: .top,
-                                            multiplier: 1,
-                                            constant: 20),
-                         NSLayoutConstraint(item: message,
-                                            attribute: .bottom,
-                                            relatedBy: .equal,
-                                            toItem: scrollView.contentLayoutGuide,
-                                            attribute: .bottomMargin,
-                                            multiplier: 1,
-                                            constant: -20)]
-      } else {
-        constraints += [NSLayoutConstraint(item: name,
-                                          attribute: .top,
-                                          relatedBy: .equal,
-                                          toItem: scrollView,
-                                          attribute: .top,
-                                          multiplier: 1,
-                                          constant: 20),
-                       NSLayoutConstraint(item: message,
-                                          attribute: .bottom,
-                                          relatedBy: .equal,
-                                          toItem: scrollView,
-                                          attribute: .bottomMargin,
-                                          multiplier: 1,
-                                          constant: -20)]
-      }
-    #else
+    if #available(iOS 11.0, *) {
+      constraints += [NSLayoutConstraint(item: name,
+                                         attribute: .top,
+                                         relatedBy: .equal,
+                                         toItem: scrollView.contentLayoutGuide,
+                                         attribute: .top,
+                                         multiplier: 1,
+                                         constant: 20),
+                      NSLayoutConstraint(item: message,
+                                         attribute: .bottom,
+                                         relatedBy: .equal,
+                                         toItem: scrollView.contentLayoutGuide,
+                                         attribute: .bottomMargin,
+                                         multiplier: 1,
+                                         constant: -20)]
+    } else {
       constraints += [NSLayoutConstraint(item: name,
                                          attribute: .top,
                                          relatedBy: .equal,
@@ -267,7 +246,7 @@ final class TextFieldOutlinedSwiftExample: UIViewController {
                                          attribute: .bottomMargin,
                                          multiplier: 1,
                                          constant: -20)]
-      #endif
+    }
 
     let stateZipViews = [ "state": state, "zip": zip ]
     constraints += NSLayoutConstraint.constraints(withVisualFormat: "H:|[state(80)]-[zip]|",
@@ -336,14 +315,15 @@ extension TextFieldOutlinedSwiftExample: UITextFieldDelegate {
 
     if textField == state {
       if let range = fullString.rangeOfCharacter(from: CharacterSet.letters.inverted),
-        fullString[range].characterCount > 0 {
+        String(fullString[range]).characterCount > 0 {
         stateController.setErrorText("Error: State can only contain letters",
                                      errorAccessibilityValue: nil)
       } else {
         stateController.setErrorText(nil, errorAccessibilityValue: nil)
       }
-    } else if textField == zip {      if let range = fullString.rangeOfCharacter(from: CharacterSet.letters),
-        fullString[range].characterCount > 0 {
+    } else if textField == zip {
+      if let range = fullString.rangeOfCharacter(from: CharacterSet.letters),
+        String(fullString[range]).characterCount > 0 {
         zipController.setErrorText("Error: Zip can only contain numbers",
                                    errorAccessibilityValue: nil)
       } else if fullString.characterCount > 5 {
@@ -354,7 +334,7 @@ extension TextFieldOutlinedSwiftExample: UITextFieldDelegate {
       }
     } else if textField == city {
       if let range = fullString.rangeOfCharacter(from: CharacterSet.decimalDigits),
-        fullString[range].characterCount > 0 {
+        String(fullString[range]).characterCount > 0 {
         cityController.setErrorText("Error: City can only contain letters",
                                     errorAccessibilityValue: nil)
       } else {
@@ -391,22 +371,22 @@ extension TextFieldOutlinedSwiftExample {
     notificationCenter.addObserver(
       self,
       selector: #selector(keyboardWillShow(notif:)),
-      name: .UIKeyboardWillChangeFrame,
+      name: UIResponder.keyboardWillChangeFrameNotification,
       object: nil)
     notificationCenter.addObserver(
       self,
       selector: #selector(keyboardWillShow(notif:)),
-      name: .UIKeyboardWillShow,
+      name: UIResponder.keyboardWillShowNotification,
       object: nil)
     notificationCenter.addObserver(
       self,
       selector: #selector(keyboardWillHide(notif:)),
-      name: .UIKeyboardWillHide,
+      name: UIResponder.keyboardWillHideNotification,
       object: nil)
   }
 
   @objc func keyboardWillShow(notif: Notification) {
-    guard let frame = notif.userInfo?[UIKeyboardFrameEndUserInfoKey] as? CGRect else {
+    guard let frame = notif.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? CGRect else {
       return
     }
     scrollView.contentInset = UIEdgeInsets(top: 0.0,
diff --git a/components/TextFields/examples/TextFieldSemanticColorThemer.swift b/components/TextFields/examples/TextFieldSemanticColorThemer.swift
index b30ed50c4c2..d66c1364bbf 100644
--- a/components/TextFields/examples/TextFieldSemanticColorThemer.swift
+++ b/components/TextFields/examples/TextFieldSemanticColorThemer.swift
@@ -102,7 +102,6 @@ final class TextFieldSemanticColorThemer: UIViewController {
                                        multiplier: 1,
                                        constant: 0)]
 
-    #if swift(>=3.2)
     if #available(iOS 11.0, *) {
       constraints += [NSLayoutConstraint(item: textfieldStandard,
                                          attribute: .top,
@@ -134,22 +133,6 @@ final class TextFieldSemanticColorThemer: UIViewController {
                                          multiplier: 1,
                                          constant: -20)]
     }
-    #else
-    constraints += [NSLayoutConstraint(item: textfieldStandard,
-                                       attribute: .top,
-                                       relatedBy: .equal,
-                                       toItem: scrollView,
-                                       attribute: .top,
-                                       multiplier: 1,
-                                       constant: 20),
-                    NSLayoutConstraint(item: textfieldAlternative,
-                                       attribute: .bottom,
-                                       relatedBy: .equal,
-                                       toItem: scrollView,
-                                       attribute: .bottomMargin,
-                                       multiplier: 1,
-                                       constant: -20)]
-    #endif
 
     NSLayoutConstraint.activate(constraints)
   }
@@ -195,22 +178,22 @@ extension TextFieldSemanticColorThemer {
     notificationCenter.addObserver(
       self,
       selector: #selector(keyboardWillShow(notif:)),
-      name: .UIKeyboardWillChangeFrame,
+      name: UIResponder.keyboardWillChangeFrameNotification,
       object: nil)
     notificationCenter.addObserver(
       self,
       selector: #selector(keyboardWillShow(notif:)),
-      name: .UIKeyboardWillShow,
+      name: UIResponder.keyboardWillShowNotification,
       object: nil)
     notificationCenter.addObserver(
       self,
       selector: #selector(keyboardWillHide(notif:)),
-      name: .UIKeyboardWillHide,
+      name: UIResponder.keyboardWillHideNotification,
       object: nil)
   }
 
   @objc func keyboardWillShow(notif: Notification) {
-    guard let frame = notif.userInfo?[UIKeyboardFrameEndUserInfoKey] as? CGRect else {
+    guard let frame = notif.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? CGRect else {
       return
     }
     scrollView.contentInset = UIEdgeInsets(top: 0.0,
diff --git a/components/TextFields/examples/TextFieldUnderlineExample.swift b/components/TextFields/examples/TextFieldUnderlineExample.swift
index a301384053c..317397ffcba 100644
--- a/components/TextFields/examples/TextFieldUnderlineExample.swift
+++ b/components/TextFields/examples/TextFieldUnderlineExample.swift
@@ -151,15 +151,8 @@ final class TextFieldUnderlineSwiftExample: UIViewController {
     scrollView.addSubview(message)
     let messageController = MDCTextInputControllerUnderline(textInput: message)
     message.textView?.delegate = self
-    #if swift(>=3.2)
-      message.text = """
-      This is where you could put a multi-line message like an email.
-
-      It can even handle new lines.
-      """
-    #else
-      message.text = "This is where you could put a multi-line message like an email. It can even handle new lines./n"
-    #endif
+    message.text = "This is where you could put a multi-line message like an email." + "\n\n" +
+      "It can even handle new lines."
     message.multilineDelegate = self
     messageController.placeholderText = "Message"
     allTextFieldControllers.append(messageController)
@@ -202,39 +195,22 @@ final class TextFieldUnderlineSwiftExample: UIViewController {
                                                   metrics: nil,
                                                   views: views)
 
-    #if swift(>=3.2)
-      if #available(iOS 11.0, *) {
-        constraints += [NSLayoutConstraint(item: name,
-                                           attribute: .top,
-                                           relatedBy: .equal,
-                                           toItem: scrollView.contentLayoutGuide,
-                                           attribute: .top,
-                                           multiplier: 1,
-                                           constant: 20),
-                        NSLayoutConstraint(item: message,
-                                           attribute: .bottom,
-                                           relatedBy: .equal,
-                                           toItem: scrollView.contentLayoutGuide,
-                                           attribute: .bottomMargin,
-                                           multiplier: 1,
-                                           constant: -20)]
-      } else {
-        constraints += [NSLayoutConstraint(item: name,
-                                           attribute: .top,
-                                           relatedBy: .equal,
-                                           toItem: scrollView,
-                                           attribute: .top,
-                                           multiplier: 1,
-                                           constant: 20),
-                        NSLayoutConstraint(item: message,
-                                           attribute: .bottom,
-                                           relatedBy: .equal,
-                                           toItem: scrollView,
-                                           attribute: .bottomMargin,
-                                           multiplier: 1,
-                                           constant: -20)]
-      }
-    #else
+    if #available(iOS 11.0, *) {
+      constraints += [NSLayoutConstraint(item: name,
+                                         attribute: .top,
+                                         relatedBy: .equal,
+                                         toItem: scrollView.contentLayoutGuide,
+                                         attribute: .top,
+                                         multiplier: 1,
+                                         constant: 20),
+                      NSLayoutConstraint(item: message,
+                                         attribute: .bottom,
+                                         relatedBy: .equal,
+                                         toItem: scrollView.contentLayoutGuide,
+                                         attribute: .bottomMargin,
+                                         multiplier: 1,
+                                         constant: -20)]
+    } else {
       constraints += [NSLayoutConstraint(item: name,
                                          attribute: .top,
                                          relatedBy: .equal,
@@ -249,7 +225,7 @@ final class TextFieldUnderlineSwiftExample: UIViewController {
                                          attribute: .bottomMargin,
                                          multiplier: 1,
                                          constant: -20)]
-    #endif
+    }
 
     let stateZipViews = [ "state": state, "zip": zip ]
     constraints += NSLayoutConstraint.constraints(withVisualFormat: "H:|[state(80)]-[zip]|",
@@ -335,7 +311,7 @@ extension TextFieldUnderlineSwiftExample: UITextFieldDelegate {
 
     if textField == state {
       if let range = fullString.rangeOfCharacter(from: CharacterSet.letters.inverted),
-        fullString[range].characterCount > 0 {
+        String(fullString[range]).characterCount > 0 {
         stateController.setErrorText("Error: State can only contain letters",
                                    errorAccessibilityValue: nil)
       } else {
@@ -343,7 +319,7 @@ extension TextFieldUnderlineSwiftExample: UITextFieldDelegate {
       }
     } else if textField == zip {
       if let range = fullString.rangeOfCharacter(from: CharacterSet.letters),
-        fullString[range].characterCount > 0 {
+        String(fullString[range]).characterCount > 0 {
         zipController.setErrorText("Error: Zip can only contain numbers",
                                    errorAccessibilityValue: nil)
       } else if fullString.characterCount > 5 {
@@ -354,7 +330,7 @@ extension TextFieldUnderlineSwiftExample: UITextFieldDelegate {
       }
     } else if textField == city {
       if let range = fullString.rangeOfCharacter(from: CharacterSet.decimalDigits),
-        fullString[range].characterCount > 0 {
+        String(fullString[range]).characterCount > 0 {
         cityController.setErrorText("Error: City can only contain letters",
                                     errorAccessibilityValue: nil)
       } else {
@@ -397,22 +373,22 @@ extension TextFieldUnderlineSwiftExample {
     notificationCenter.addObserver(
       self,
       selector: #selector(keyboardWillShow(notif:)),
-      name: .UIKeyboardWillShow,
+      name: UIResponder.keyboardWillShowNotification,
       object: nil)
     notificationCenter.addObserver(
       self,
       selector: #selector(keyboardWillHide(notif:)),
-      name: .UIKeyboardWillHide,
+      name: UIResponder.keyboardWillHideNotification,
       object: nil)
     notificationCenter.addObserver(
       self,
       selector: #selector(keyboardWillShow(notif:)),
-      name: .UIKeyboardWillChangeFrame,
+      name: UIResponder.keyboardWillChangeFrameNotification,
       object: nil)
   }
 
   @objc func keyboardWillShow(notif: Notification) {
-    guard let frame = notif.userInfo?[UIKeyboardFrameEndUserInfoKey] as? CGRect else {
+    guard let frame = notif.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? CGRect else {
       return
     }
     scrollView.contentInset = UIEdgeInsets(top: 0.0,
@@ -450,10 +426,6 @@ extension TextFieldUnderlineSwiftExample {
 
 internal extension String {
   var characterCount: Int {
-    #if swift(>=3.2)
-      return self.count
-    #else
-      return self.characters.count
-    #endif
+    return self.count
   }
 }
diff --git a/components/TextFields/examples/experimental/InputTextFieldStoryboardExampleViewController.swift b/components/TextFields/examples/experimental/InputTextFieldStoryboardExampleViewController.swift
index 751de6f5097..36efc8d5b2b 100644
--- a/components/TextFields/examples/experimental/InputTextFieldStoryboardExampleViewController.swift
+++ b/components/TextFields/examples/experimental/InputTextFieldStoryboardExampleViewController.swift
@@ -60,22 +60,22 @@ extension SimpleTextFieldStoryboardExampleViewController {
     notificationCenter.addObserver(
       self,
       selector: #selector(keyboardWillShow(notif:)),
-      name: .UIKeyboardWillShow,
+      name: UIResponder.keyboardWillShowNotification,
       object: nil)
     notificationCenter.addObserver(
       self,
       selector: #selector(keyboardWillHide(notif:)),
-      name: .UIKeyboardWillHide,
+      name: UIResponder.keyboardWillHideNotification,
       object: nil)
     notificationCenter.addObserver(
       self,
       selector: #selector(keyboardWillShow(notif:)),
-      name: .UIKeyboardWillChangeFrame,
+      name: UIResponder.keyboardWillChangeFrameNotification,
       object: nil)
   }
   
   @objc func keyboardWillShow(notif: Notification) {
-    guard let _ = notif.userInfo?[UIKeyboardFrameEndUserInfoKey] as? CGRect else {
+    guard let _ = notif.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? CGRect else {
       return
     }
   }
diff --git a/components/TextFields/examples/supplemental/TextFieldKitchenSinkExampleSupplemental.swift b/components/TextFields/examples/supplemental/TextFieldKitchenSinkExampleSupplemental.swift
index 44766d7f094..0ce6c293154 100644
--- a/components/TextFields/examples/supplemental/TextFieldKitchenSinkExampleSupplemental.swift
+++ b/components/TextFields/examples/supplemental/TextFieldKitchenSinkExampleSupplemental.swift
@@ -52,7 +52,7 @@ extension TextFieldKitchenSinkSwiftExample {
 
     NotificationCenter.default.addObserver(self,
                                            selector: #selector(TextFieldKitchenSinkSwiftExample.contentSizeCategoryDidChange(notif:)),
-                                           name:.UIContentSizeCategoryDidChange,
+                                           name: UIContentSizeCategory.didChangeNotification,
                                            object: nil)
   }
 
@@ -184,7 +184,7 @@ extension TextFieldKitchenSinkSwiftExample {
       control
     }
 
-    let allTextFields = allTextFieldControllers.flatMap { $0.textInput }
+    let allTextFields = allTextFieldControllers.compactMap { $0.textInput }
     let textFieldsString = allTextFields.reduce("", concatenatingClosure)
 
     var textFields = [String: UIView]()
@@ -192,7 +192,7 @@ extension TextFieldKitchenSinkSwiftExample {
       textFields[unique(from: textInput, with: prefix)] = textInput
     }
 
-    let allTextViews = allMultilineTextFieldControllers.flatMap { $0.textInput }
+    let allTextViews = allMultilineTextFieldControllers.compactMap { $0.textInput }
     let textViewsString = allTextViews.reduce("", concatenatingClosure)
 
     var textViews = [String: UIView]()
@@ -228,7 +228,7 @@ extension TextFieldKitchenSinkSwiftExample {
                                          attribute: .leadingMargin,
                                          multiplier: 1.0,
                                          constant: 0.0)
-        leading.priority = 750.0
+        leading.priority = UILayoutPriority.defaultHigh
         leading.isActive = true
 
         let trailing = NSLayoutConstraint(item: value,
@@ -238,7 +238,7 @@ extension TextFieldKitchenSinkSwiftExample {
                                           attribute: .trailing,
                                           multiplier: 1.0,
                                           constant: 0.0)
-        trailing.priority = 750.0
+        trailing.priority = UILayoutPriority.defaultHigh
         trailing.isActive = true
       }
     }
@@ -248,7 +248,7 @@ extension TextFieldKitchenSinkSwiftExample {
                                                                metrics: nil,
                                                                views: views))
 
-    controllersFullWidth.flatMap { $0.textInput }.forEach { textInput in
+    controllersFullWidth.compactMap { $0.textInput }.forEach { textInput in
       NSLayoutConstraint(item: textInput,
                          attribute: .leading,
                          relatedBy: .equal,
@@ -275,54 +275,37 @@ extension TextFieldKitchenSinkSwiftExample {
     }
 
     // These used to be done in the visual format string but iOS 11 changed that.
-    #if swift(>=3.2)
-      if #available(iOS 11.0, *) {
-        NSLayoutConstraint(item: singleLabel,
-                           attribute: .topMargin,
-                           relatedBy: .equal,
-                           toItem: scrollView.contentLayoutGuide,
-                           attribute: .top,
-                           multiplier: 1.0,
-                           constant: 20).isActive = true
-        NSLayoutConstraint(item: allControls.last as Any,
-                           attribute: .bottom,
-                           relatedBy: .equal,
-                           toItem: scrollView.contentLayoutGuide,
-                           attribute: .bottomMargin,
-                           multiplier: 1.0,
-                           constant: -20).isActive = true
-      } else {
-        NSLayoutConstraint(item: singleLabel,
-                           attribute: .topMargin,
-                           relatedBy: .equal,
-                           toItem: scrollView,
-                           attribute: .top,
-                           multiplier: 1.0,
-                           constant: 20).isActive = true
-        NSLayoutConstraint(item: allControls.last as Any,
-                           attribute: .bottom,
-                           relatedBy: .equal,
-                           toItem: scrollView,
-                           attribute: .bottomMargin,
-                           multiplier: 1.0,
-                           constant: -20).isActive = true
-      }
-      #else
-        NSLayoutConstraint(item: singleLabel,
-                           attribute: .topMargin,
-                           relatedBy: .equal,
-                           toItem: scrollView,
-                           attribute: .top,
-                           multiplier: 1.0,
-                           constant: 20).isActive = true
-        NSLayoutConstraint(item: allControls.last as Any,
-                           attribute: .bottom,
-                           relatedBy: .equal,
-                           toItem: scrollView,
-                           attribute: .bottomMargin,
-                           multiplier: 1.0,
-                           constant: -20).isActive = true
-      #endif
+    if #available(iOS 11.0, *) {
+      NSLayoutConstraint(item: singleLabel,
+                         attribute: .topMargin,
+                         relatedBy: .equal,
+                         toItem: scrollView.contentLayoutGuide,
+                         attribute: .top,
+                         multiplier: 1.0,
+                         constant: 20).isActive = true
+      NSLayoutConstraint(item: allControls.last as Any,
+                         attribute: .bottom,
+                         relatedBy: .equal,
+                         toItem: scrollView.contentLayoutGuide,
+                         attribute: .bottomMargin,
+                         multiplier: 1.0,
+                         constant: -20).isActive = true
+    } else {
+      NSLayoutConstraint(item: singleLabel,
+                         attribute: .topMargin,
+                         relatedBy: .equal,
+                         toItem: scrollView,
+                         attribute: .top,
+                         multiplier: 1.0,
+                         constant: 20).isActive = true
+      NSLayoutConstraint(item: allControls.last as Any,
+                         attribute: .bottom,
+                         relatedBy: .equal,
+                         toItem: scrollView,
+                         attribute: .bottomMargin,
+                         multiplier: 1.0,
+                         constant: -20).isActive = true
+    }
 
     registerKeyboardNotifications()
     addGestureRecognizer()
@@ -339,22 +322,22 @@ extension TextFieldKitchenSinkSwiftExample {
     notificationCenter.addObserver(
       self,
       selector: #selector(TextFieldKitchenSinkSwiftExample.keyboardWillShow(notif:)),
-      name: .UIKeyboardWillShow,
+      name: UIResponder.keyboardWillShowNotification,
       object: nil)
     notificationCenter.addObserver(
       self,
       selector: #selector(TextFieldKitchenSinkSwiftExample.keyboardWillShow(notif:)),
-      name: .UIKeyboardWillChangeFrame,
+      name: UIResponder.keyboardWillChangeFrameNotification,
       object: nil)
     notificationCenter.addObserver(
       self,
       selector: #selector(TextFieldKitchenSinkSwiftExample.keyboardWillHide(notif:)),
-      name: .UIKeyboardWillHide,
+      name: UIResponder.keyboardWillHideNotification,
       object: nil)
   }
 
   @objc func keyboardWillShow(notif: Notification) {
-    guard let frame = notif.userInfo?[UIKeyboardFrameEndUserInfoKey] as? CGRect else {
+    guard let frame = notif.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? CGRect else {
       return
     }
     scrollView.contentInset = UIEdgeInsets(top: 0.0,
@@ -389,7 +372,7 @@ extension TextFieldKitchenSinkSwiftExample {
       partialTitle = "Underline View Mode"
     }
 
-    let closure: (UITextFieldViewMode, String) -> Void = { mode, title in
+    let closure: (UITextField.ViewMode, String) -> Void = { mode, title in
       controllersToChange.forEach { controller in
         if button == self.characterModeButton {
           controller.characterCountViewMode = mode
@@ -413,10 +396,10 @@ extension TextFieldKitchenSinkSwiftExample {
 
   func presentAlert (alert: UIAlertController,
                      partialTitle: String,
-                     closure: @escaping (_ mode: UITextFieldViewMode, _ title: String) -> Void) -> Void {
+                     closure: @escaping (_ mode: UITextField.ViewMode, _ title: String) -> Void) -> Void {
 
     for rawMode in 0...3 {
-      let mode = UITextFieldViewMode(rawValue: rawMode)!
+      let mode = UITextField.ViewMode(rawValue: rawMode)!
       alert.addAction(UIAlertAction(title: modeName(mode: mode),
                                     style: .default,
                                     handler: { _ in
@@ -427,7 +410,7 @@ extension TextFieldKitchenSinkSwiftExample {
     present(alert, animated: true, completion: nil)
   }
 
-  func modeName(mode: UITextFieldViewMode) -> String {
+  func modeName(mode: UITextField.ViewMode) -> String {
     switch mode {
     case .always:
       return "Always"
diff --git a/components/TextFields/tests/unit/TextFieldControllerLegacyTests.swift b/components/TextFields/tests/unit/TextFieldControllerLegacyTests.swift
index 420615e4126..fb2ffd436c7 100644
--- a/components/TextFields/tests/unit/TextFieldControllerLegacyTests.swift
+++ b/components/TextFields/tests/unit/TextFieldControllerLegacyTests.swift
@@ -253,7 +253,7 @@ class TextFieldControllerDefaultLegacyTests: XCTestCase {
     textField.setNeedsLayout()
     textField.layoutIfNeeded()
 
-    let estimatedTextFrame = UIEdgeInsetsInsetRect(textField.bounds, controller.textInsets(UIEdgeInsets()))
+    let estimatedTextFrame = textField.bounds.inset(by: controller.textInsets(UIEdgeInsets()))
     XCTAssertFalse(textField.placeholderLabel.frame.intersects(estimatedTextFrame))
   }
 
diff --git a/components/TextFields/tests/unit/TextFieldTests.swift b/components/TextFields/tests/unit/TextFieldTests.swift
index 8d886df44dc..124fbab05bc 100644
--- a/components/TextFields/tests/unit/TextFieldTests.swift
+++ b/components/TextFields/tests/unit/TextFieldTests.swift
@@ -33,7 +33,9 @@ class TextFieldTests: XCTestCase {
     let textField = MDCTextField()
 
     for constraint in textField.constraints {
-      XCTAssertLessThanOrEqual(constraint.priority, UILayoutPriorityDefaultLow + 10, String(describing: constraint))
+      XCTAssertLessThanOrEqual(constraint.priority.rawValue,
+                               UILayoutPriority.defaultLow.rawValue + 10,
+                               String(describing: constraint))
     }
   }
 
@@ -47,7 +49,8 @@ class TextFieldTests: XCTestCase {
 
     textField.textInsetsMode = .never
     textField.borderView?.borderFillColor = .purple
-    textField.borderView?.borderPath = UIBezierPath(ovalIn: CGRect(x: 0, y: 0, width: 100, height: 100))
+    textField.borderView?.borderPath =
+      UIBezierPath(ovalIn: CGRect(x: 0, y: 0, width: 100, height: 100))
     textField.borderView?.borderStrokeColor = .yellow
     textField.clearButton.tintColor = .red
     textField.clearButtonMode = .always
@@ -67,9 +70,12 @@ class TextFieldTests: XCTestCase {
       XCTAssertEqual(textField.textInsetsMode, textFieldCopy.textInsetsMode)
       XCTAssertEqual(textField.attributedPlaceholder, textFieldCopy.attributedPlaceholder)
       XCTAssertEqual(textField.attributedText, textFieldCopy.attributedText)
-      XCTAssertEqual(textField.borderView?.borderFillColor, textFieldCopy.borderView?.borderFillColor)
-      XCTAssertEqual(textField.borderView?.borderPath?.bounds.integral, textFieldCopy.borderView?.borderPath?.bounds.integral)
-      XCTAssertEqual(textField.borderView?.borderStrokeColor, textFieldCopy.borderView?.borderStrokeColor)
+      XCTAssertEqual(textField.borderView?.borderFillColor,
+                     textFieldCopy.borderView?.borderFillColor)
+      XCTAssertEqual(textField.borderView?.borderPath?.bounds.integral,
+                     textFieldCopy.borderView?.borderPath?.bounds.integral)
+      XCTAssertEqual(textField.borderView?.borderStrokeColor,
+                     textFieldCopy.borderView?.borderStrokeColor)
       XCTAssertEqual(textField.clearButton.tintColor, textFieldCopy.clearButton.tintColor)
       XCTAssertEqual(textField.clearButtonMode, textFieldCopy.clearButtonMode)
       XCTAssertEqual(textField.cursorColor, textFieldCopy.cursorColor)
diff --git a/components/Typography/examples/TypographyFontListExample.swift b/components/Typography/examples/TypographyFontListExample.swift
index 7b8526121c7..86322cdbaf2 100644
--- a/components/Typography/examples/TypographyFontListExample.swift
+++ b/components/Typography/examples/TypographyFontListExample.swift
@@ -24,7 +24,7 @@ class TypographyFontListExampleViewController: UITableViewController {
 
     self.tableView.separatorStyle = .none
 
-    self.tableView.rowHeight = UITableViewAutomaticDimension
+    self.tableView.rowHeight = UITableView.automaticDimension
     self.tableView.estimatedRowHeight = 50
   }
 
@@ -64,7 +64,7 @@ class TypographyFontListExampleViewController: UITableViewController {
     self.init(style: .plain)
   }
 
-  override init(style: UITableViewStyle) {
+  override init(style: UITableView.Style) {
     super.init(style: style)
 
     self.title = "Font list"
diff --git a/components/private/Dragons/examples/ZShadow.swift b/components/private/Dragons/examples/ZShadow.swift
index b938cc5007f..82c2de18e8c 100644
--- a/components/private/Dragons/examples/ZShadow.swift
+++ b/components/private/Dragons/examples/ZShadow.swift
@@ -84,7 +84,7 @@ class ZShadowViewController: UIViewController {
     
   }
   
-  func squaresTapped() {
+  @objc func squaresTapped() {
     greenBannerLeadingConstraintCollapsed.isActive = !greenBannerLeadingConstraintCollapsed.isActive
     blueBannerLeadingConstraintCollapsed.isActive = !blueBannerLeadingConstraintCollapsed.isActive
     
diff --git a/components/private/Snapshot/BUILD b/components/private/Snapshot/BUILD
index c3dc7ea0fcd..dabeba80dce 100644
--- a/components/private/Snapshot/BUILD
+++ b/components/private/Snapshot/BUILD
@@ -34,7 +34,7 @@ swift_library(
     srcs = glob(["src/*.swift"]),
     copts = [
         "-swift-version",
-        "3",
+        "4.2",
     ],
 )
 
diff --git a/material_components_ios.bzl b/material_components_ios.bzl
index 9a0092ade6a..2fc5416ecd6 100644
--- a/material_components_ios.bzl
+++ b/material_components_ios.bzl
@@ -158,7 +158,7 @@ def mdc_examples_swift_library(
       visibility = visibility,
       copts = [
           "-swift-version",
-          "3",
+          "4.2",
       ],
       srcs = native.glob([
           "examples/*.swift",