diff --git a/.gitignore b/.gitignore
index efd5d78..1c7cab1 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,3 +5,5 @@ Package.resolved
 /*.xcodeproj
 xcuserdata/
 .swiftpm
+.vscode/
+.history
diff --git a/Sources/InstrumentationBaggage/Baggage.swift b/Sources/InstrumentationBaggage/Baggage.swift
index 267e56a..474bd4f 100644
--- a/Sources/InstrumentationBaggage/Baggage.swift
+++ b/Sources/InstrumentationBaggage/Baggage.swift
@@ -13,6 +13,12 @@
 //
 //===----------------------------------------------------------------------===//
 
+#if swift(>=5.5) && canImport(_Concurrency)
+public typealias _Baggage_Sendable = Swift.Sendable
+#else
+public typealias _Baggage_Sendable = Any
+#endif
+
 /// A `Baggage` is a heterogeneous storage type with value semantics for keyed values in a type-safe fashion.
 ///
 /// Its values are uniquely identified via `BaggageKey`s (by type identity). These keys also dictate the type of
@@ -65,8 +71,8 @@
 /// `Baggage` does not expose more functions on purpose to prevent abuse and treating it as too much of an
 /// arbitrary value smuggling container, but only make it convenient for tracing and instrumentation systems which need
 /// to access either specific or all items carried inside a baggage.
-public struct Baggage {
-    private var _storage = [AnyBaggageKey: Any]()
+public struct Baggage: _Baggage_Sendable {
+    private var _storage = [AnyBaggageKey: _Baggage_Sendable]()
 
     /// Internal on purpose, please use `Baggage.TODO` or `Baggage.topLevel` to create an "empty" baggage,
     /// which carries more meaning to other developers why an empty baggage was used.
@@ -151,7 +157,7 @@ extension Baggage {
 
 /// Carried automatically by a "to do" baggage.
 /// It can be used to track where a baggage originated and which "to do" baggage must be fixed into a real one to avoid this.
-public struct TODOLocation {
+public struct TODOLocation: _Baggage_Sendable {
     /// Source file location where the to-do `Baggage` was created
     public let file: String
     /// Source line location where the to-do `Baggage` was created
diff --git a/Sources/InstrumentationBaggage/BaggageKey.swift b/Sources/InstrumentationBaggage/BaggageKey.swift
index 2e2d8f2..7f01205 100644
--- a/Sources/InstrumentationBaggage/BaggageKey.swift
+++ b/Sources/InstrumentationBaggage/BaggageKey.swift
@@ -39,9 +39,9 @@
 ///     }
 ///
 /// This pattern allows library authors fine-grained control over which values may be set, and which only get by end-users.
-public protocol BaggageKey {
+public protocol BaggageKey: _Baggage_Sendable {
     /// The type of value uniquely identified by this key.
-    associatedtype Value
+    associatedtype Value: _Baggage_Sendable
 
     /// The human-readable name of this key.
     /// This name will be used instead of the type name when a value is printed.
@@ -62,7 +62,7 @@ extension BaggageKey {
 }
 
 /// A type-erased `BaggageKey` used when iterating through the `Baggage` using its `forEach` method.
-public struct AnyBaggageKey {
+public struct AnyBaggageKey: _Baggage_Sendable {
     /// The key's type represented erased to an `Any.Type`.
     public let keyType: Any.Type
 
diff --git a/docker/docker-compose.2004.54.yaml b/docker/docker-compose.2004.54.yaml
new file mode 100644
index 0000000..868c738
--- /dev/null
+++ b/docker/docker-compose.2004.54.yaml
@@ -0,0 +1,18 @@
+version: "3"
+
+services:
+
+  runtime-setup:
+    image: swift-distributed-tracing-baggage:20.04-5.4
+    build:
+      args:
+        ubuntu_version: "focal"
+        swift_version: "5.4"
+
+  test:
+    image: swift-distributed-tracing-baggage:20.04-5.4
+    environment: []
+      #- SANITIZER_ARG=--sanitize=thread
+
+  shell:
+    image: swift-distributed-tracing-baggage:20.04-5.4
\ No newline at end of file
diff --git a/docker/docker-compose.2004.55.yaml b/docker/docker-compose.2004.55.yaml
new file mode 100644
index 0000000..15e51e2
--- /dev/null
+++ b/docker/docker-compose.2004.55.yaml
@@ -0,0 +1,18 @@
+version: "3"
+
+services:
+
+  runtime-setup:
+    image: swift-distributed-tracing-baggage:20.04-5.5
+    build:
+      args:
+        ubuntu_version: "focal"
+        swift_version: "5.5"
+
+  test:
+    image: swift-distributed-tracing-baggage:20.04-5.5
+    environment: []
+      #- SANITIZER_ARG=--sanitize=thread
+
+  shell:
+    image: swift-distributed-tracing-baggage:20.04-5.5
diff --git a/docker/docker-compose.2004.main.yaml b/docker/docker-compose.2004.main.yaml
new file mode 100644
index 0000000..c138963
--- /dev/null
+++ b/docker/docker-compose.2004.main.yaml
@@ -0,0 +1,17 @@
+version: "3"
+
+services:
+
+  runtime-setup:
+    image: swift-distributed-tracing-baggage:20.04-main
+    build:
+      args:
+        base_image: "swiftlang/swift:nightly-main-focal"
+
+
+  test:
+    image: swift-distributed-tracing-baggage:20.04-main
+    environment: []
+      #- SANITIZER_ARG=--sanitize=thread
+  shell:
+    image: swift-distributed-tracing-baggage:20.04-main
\ No newline at end of file