diff --git a/README.md b/README.md
index 0252e6d1..477e4838 100644
--- a/README.md
+++ b/README.md
@@ -15,6 +15,10 @@ Try Spree Product Subscriptions for Spree master with direct deployment on Herok
 
 [![Deploy](https://www.herokucdn.com/deploy/button.svg)](https://heroku.com/deploy?template=https://github.com/vinsol-spree-contrib/spree-demo-heroku/tree/spree-product-subscriptions-master)
 
+Try Spree Product Subscriptions for Spree 4 with direct deployment on Heroku:
+
+[![Deploy](https://www.herokucdn.com/deploy/button.svg)](https://heroku.com/deploy?template=https://github.com/vinsol-spree-contrib/spree-demo-heroku/tree/spree-product-subscriptions-4-1)
+
 Try Spree Product Subscriptions for Spree 3-4 with direct deployment on Heroku:
 
 [![Deploy](https://www.herokucdn.com/deploy/button.svg)](https://heroku.com/deploy?template=https://github.com/vinsol-spree-contrib/spree-demo-heroku/tree/spree-product-subscriptions-3-4)
diff --git a/app/assets/javascripts/spree/backend/subscribable.js b/app/assets/javascripts/spree/backend/subscribable.js
index 863978d3..92a386fb 100644
--- a/app/assets/javascripts/spree/backend/subscribable.js
+++ b/app/assets/javascripts/spree/backend/subscribable.js
@@ -23,12 +23,12 @@ Subscribable.prototype.bindParentCheckboxEvent = function() {
 };
 
 Subscribable.prototype.enableChildCheckboxes = function() {
-  this.$childCheckboxesDiv.removeClass("hidden");
+  this.$childCheckboxesDiv.removeClass("is-hidden");
   this.$childCheckboxesDiv.find("input").removeAttr("disabled");
 };
 
 Subscribable.prototype.disableChildCheckboxes = function() {
-  this.$childCheckboxesDiv.addClass("hidden");
+  this.$childCheckboxesDiv.addClass("is-hidden");
   this.$childCheckboxesDiv.find("input").attr("disabled", "disabled");
 }
 
diff --git a/app/assets/javascripts/spree/frontend/cart_form_subscription_button.js b/app/assets/javascripts/spree/frontend/cart_form_subscription_button.js
new file mode 100644
index 00000000..10effb34
--- /dev/null
+++ b/app/assets/javascripts/spree/frontend/cart_form_subscription_button.js
@@ -0,0 +1,14 @@
+Spree.ready(function($) {
+  Spree.addToCartFormSubmissionOptions = function() {
+    $cartForm = $(ADD_TO_CART_FORM_SELECTOR);
+    if($cartForm.find('.cart_radio_button:checked').val() == ".subscription_options") {
+      options = {
+        subscribe: true,
+        subscription_frequency_id: $cartForm.find('#subscription_subscription_frequency_id option:selected').val(),
+        delivery_number: parseInt($cartForm.find('#subscription_delivery_number').val())
+      };
+      return options;
+    }
+    return {};
+  }
+})
\ No newline at end of file
diff --git a/app/assets/javascripts/spree/frontend/cart_radio_button.js b/app/assets/javascripts/spree/frontend/cart_radio_button.js
index 1f699b32..86ab7082 100644
--- a/app/assets/javascripts/spree/frontend/cart_radio_button.js
+++ b/app/assets/javascripts/spree/frontend/cart_radio_button.js
@@ -14,17 +14,14 @@ CartRadioButton.prototype.bindEvents = function() {
 };
 
 CartRadioButton.prototype.toggleDiv = function($checkBox) {
-  $($checkBox.val()).show();
-  this.hideOtherDivs();
-};
-
-CartRadioButton.prototype.hideOtherDivs = function() {
-  $.each(this.$radioButtons, function(index, value) {
-    $checkBox = $(value);
-    if (!$checkBox.prop("checked")) {
-      $($checkBox.val()).hide();
-    }
-  });
+  let value = $checkBox.val();
+  $(value).show();
+  if (value.includes('subscription_options')) {
+    $('#add-to-cart-button').text('SUBSCRIBE NOW');
+  } else {
+    $('#add-to-cart-button').text('ADD TO CART');
+    $(value).siblings('.subscription_options').hide();
+  }
 };
 
 $(function() {
diff --git a/app/assets/javascripts/spree/frontend/spree_product_subscriptions.js b/app/assets/javascripts/spree/frontend/spree_product_subscriptions.js
index 4aea1b53..2bc93b92 100644
--- a/app/assets/javascripts/spree/frontend/spree_product_subscriptions.js
+++ b/app/assets/javascripts/spree/frontend/spree_product_subscriptions.js
@@ -1,6 +1,7 @@
 // Placeholder manifest file.
 //= require spree/frontend/cart_radio_button.js
 //= require spree/frontend/datepicker
+//= require spree/frontend/cart_form_subscription_button
 //= require spree/frontend/ajax_handler.js
 //= require spree/frontend/update_quantity_in_cart
 // the installer will append this file to the app vendored assets here: vendor/assets/javascripts/spree/frontend/all.js'
diff --git a/app/controllers/spree/api/v1/line_items_controller_decorator.rb b/app/controllers/spree/api/v1/line_items_controller_decorator.rb
deleted file mode 100644
index 180c4c63..00000000
--- a/app/controllers/spree/api/v1/line_items_controller_decorator.rb
+++ /dev/null
@@ -1,5 +0,0 @@
-Spree::Api::V1::LineItemsController.class_eval do
-
-  self.line_item_options += [:subscribe, :delivery_number, :subscription_frequency_id]
-
-end
diff --git a/app/controllers/spree/base_controller_decorator.rb b/app/controllers/spree/base_controller_decorator.rb
deleted file mode 100644
index 8cea204b..00000000
--- a/app/controllers/spree/base_controller_decorator.rb
+++ /dev/null
@@ -1,3 +0,0 @@
-Spree::BaseController.class_eval do
-  add_flash_types :success, :error
-end
diff --git a/app/controllers/spree/orders_controller_decorator.rb b/app/controllers/spree/orders_controller_decorator.rb
deleted file mode 100644
index cb77923e..00000000
--- a/app/controllers/spree/orders_controller_decorator.rb
+++ /dev/null
@@ -1,22 +0,0 @@
-Spree::OrdersController.class_eval do
-
-  before_action :add_subscription_fields, only: :populate, if: -> { params[:subscribe].present? }
-  before_action :restrict_guest_subscription, only: :update, unless: :spree_current_user
-
-  private
-
-    def restrict_guest_subscription
-      redirect_to login_path, error: Spree.t(:required_authentication) if @order.subscriptions.present?
-    end
-
-    def add_subscription_fields
-      is_subscribed = params.fetch(:subscribe, "").present?
-
-      existing_options = {options: params.fetch(:options, {}).permit!}
-      updated_subscription_params = params.fetch(:subscription, {}).merge({subscribe: is_subscribed}).permit!
-      existing_options[:options].merge!(updated_subscription_params)
-      updated_params = params.merge!(existing_options)
-      updated_params
-    end
-
-end
diff --git a/app/controllers/spree/users_controller_decorator.rb b/app/controllers/spree/users_controller_decorator.rb
deleted file mode 100644
index 195ec98e..00000000
--- a/app/controllers/spree/users_controller_decorator.rb
+++ /dev/null
@@ -1,12 +0,0 @@
-Spree::UsersController.class_eval do
-
-  before_action :load_subscriptions, only: :show
-
-  private
-
-    def load_subscriptions
-      @orders = @user.orders.complete.order(completed_at: :desc)
-      @subscriptions = Spree::Subscription.active.order(created_at: :desc).with_parent_orders(@orders)
-    end
-
-end
diff --git a/app/controllers/spree_product_subscriptions/base_controller_decorator.rb b/app/controllers/spree_product_subscriptions/base_controller_decorator.rb
new file mode 100644
index 00000000..fce890ae
--- /dev/null
+++ b/app/controllers/spree_product_subscriptions/base_controller_decorator.rb
@@ -0,0 +1,11 @@
+module SpreeProductSubscriptions
+  module BaseControllerDecorator
+
+    def self.prepended(base)
+      base.add_flash_types :success, :error
+    end
+
+  end
+end
+
+Spree::BaseController.prepend SpreeProductSubscriptions::BaseControllerDecorator
diff --git a/app/controllers/spree_product_subscriptions/line_items_controller_decorator.rb b/app/controllers/spree_product_subscriptions/line_items_controller_decorator.rb
new file mode 100644
index 00000000..24f06f6b
--- /dev/null
+++ b/app/controllers/spree_product_subscriptions/line_items_controller_decorator.rb
@@ -0,0 +1,10 @@
+module SpreeProductSubscriptions::LineItemsControllerDecorator
+
+  def self.prepended(base)
+    base.line_item_options += [:subscribe, :delivery_number, :subscription_frequency_id]
+  end
+
+
+end
+
+Spree::Api::V1::LineItemsController.prepend SpreeProductSubscriptions::LineItemsControllerDecorator
\ No newline at end of file
diff --git a/app/controllers/spree_product_subscriptions/orders_controller_decorator.rb b/app/controllers/spree_product_subscriptions/orders_controller_decorator.rb
new file mode 100644
index 00000000..b3105030
--- /dev/null
+++ b/app/controllers/spree_product_subscriptions/orders_controller_decorator.rb
@@ -0,0 +1,14 @@
+module SpreeProductSubscriptions::OrdersControllerDecorator  
+
+  def self.prepended(base)
+    base.before_action :restrict_guest_subscription, only: :update, unless: :spree_current_user
+  end
+
+  private
+
+    def restrict_guest_subscription
+      redirect_to login_path, error: Spree.t(:required_authentication) if @order.subscriptions.present?
+    end
+end
+
+Spree::OrdersController.prepend SpreeProductSubscriptions::OrdersControllerDecorator
diff --git a/app/controllers/spree/admin/payments_controller_decorator.rb b/app/controllers/spree_product_subscriptions/payments_controller_decorator.rb
similarity index 70%
rename from app/controllers/spree/admin/payments_controller_decorator.rb
rename to app/controllers/spree_product_subscriptions/payments_controller_decorator.rb
index 8fbe173f..a10d4798 100644
--- a/app/controllers/spree/admin/payments_controller_decorator.rb
+++ b/app/controllers/spree_product_subscriptions/payments_controller_decorator.rb
@@ -1,4 +1,4 @@
-Spree::Admin::PaymentsController.class_eval do
+module SpreeProductSubscriptions::PaymentsControllerDecorator
 
   private
 
@@ -13,3 +13,5 @@ def available_payment_methods
     end
 
 end
+
+Spree::Admin::PaymentsController.prepend SpreeProductSubscriptions::PaymentsControllerDecorator
diff --git a/app/controllers/spree_product_subscriptions/users_controller_decorator.rb b/app/controllers/spree_product_subscriptions/users_controller_decorator.rb
new file mode 100644
index 00000000..947e1d76
--- /dev/null
+++ b/app/controllers/spree_product_subscriptions/users_controller_decorator.rb
@@ -0,0 +1,16 @@
+module SpreeProductSubscriptions::UsersControllerDecorator
+
+  def self.prepended(base)
+    base.before_action :load_subscriptions, only: :show
+  end
+
+  private
+
+    def load_subscriptions
+      @orders = @user.orders.complete.order(completed_at: :desc)
+      @subscriptions = Spree::Subscription.active.order(created_at: :desc).with_parent_orders(@orders)
+    end
+
+end
+
+Spree::UsersController.prepend SpreeProductSubscriptions::UsersControllerDecorator
diff --git a/app/models/spree/order_decorator.rb b/app/models/spree/order_decorator.rb
deleted file mode 100644
index 87452c93..00000000
--- a/app/models/spree/order_decorator.rb
+++ /dev/null
@@ -1,46 +0,0 @@
-Spree::Order.class_eval do
-
-  has_one :order_subscription, class_name: "Spree::OrderSubscription", dependent: :destroy
-  has_one :parent_subscription, through: :order_subscription, source: :subscription
-  has_many :subscriptions, class_name: "Spree::Subscription",
-                           foreign_key: :parent_order_id,
-                           dependent: :restrict_with_error
-
-  self.state_machine.after_transition to: :complete, do: :enable_subscriptions, if: :any_disabled_subscription?
-
-  after_update :update_subscriptions
-
-  def available_payment_methods
-    if subscriptions.exists?
-      @available_payment_methods = Spree::Gateway.active.available_on_front_end
-    else
-      @available_payment_methods ||= Spree::PaymentMethod.active.available_on_front_end
-    end
-  end
-
-  private
-
-    def enable_subscriptions
-      subscriptions.each do |subscription|
-        subscription.update(
-          source: payments.from_credit_card.first.source,
-          enabled: true,
-          ship_address: ship_address.clone,
-          bill_address: bill_address.clone
-        )
-      end
-    end
-
-    def any_disabled_subscription?
-      subscriptions.disabled.any?
-    end
-
-    def update_subscriptions
-      line_items.each do |line_item|
-        if line_item.subscription_attributes_present?
-          subscriptions.find_by(variant: line_item.variant).update(line_item.updatable_subscription_attributes)
-        end
-      end
-    end
-
-end
diff --git a/app/models/spree/product_decorator.rb b/app/models/spree/product_decorator.rb
deleted file mode 100644
index 89dda1b2..00000000
--- a/app/models/spree/product_decorator.rb
+++ /dev/null
@@ -1,15 +0,0 @@
-Spree::Product.class_eval do
-
-  has_many :subscriptions, through: :variants_including_master, source: :subscriptions, dependent: :restrict_with_error
-  has_many :product_subscription_frequencies, class_name: "Spree::ProductSubscriptionFrequency", dependent: :destroy
-  has_many :subscription_frequencies, through: :product_subscription_frequencies, dependent: :destroy
-
-  alias_attribute :subscribable, :is_subscribable
-
-  self.whitelisted_ransackable_attributes += %w( is_subscribable )
-
-  scope :subscribable, -> { where(subscribable: true) }
-
-  validates :subscription_frequencies, presence: true, if: :subscribable?
-
-end
diff --git a/app/models/spree/subscription.rb b/app/models/spree/subscription.rb
index 68efe1ee..237db7df 100644
--- a/app/models/spree/subscription.rb
+++ b/app/models/spree/subscription.rb
@@ -95,20 +95,20 @@ def number_of_deliveries_left
 
     def pause
       run_callbacks :pause do
-        update_attributes(paused: true)
+        update(paused: true)
       end
     end
 
     def unpause
       run_callbacks :unpause do
-        update_attributes(paused: false)
+        update(paused: false)
       end
     end
 
     def cancel
       self.cancelled = true
       run_callbacks :cancel do
-        update_attributes(cancelled_at: Time.current)
+        update(cancelled_at: Time.current)
       end
     end
 
@@ -189,7 +189,12 @@ def make_new_order
       end
 
       def add_variant_to_order(order)
-        order.contents.add(variant, quantity)
+        # order.contents.add(variant, quantity) Contents removed from Spree 4
+        Spree::Cart::AddItem.call(
+            order: order,
+            variant: variant,
+            quantity: quantity
+          )
         order.next
       end
 
@@ -236,7 +241,7 @@ def confirm_order(order)
       def order_attributes
         {
           currency: parent_order.currency,
-          guest_token: parent_order.guest_token,
+          token: parent_order.token,
           store: parent_order.store,
           user: parent_order.user,
           created_by: parent_order.user,
diff --git a/app/models/spree/variant_decorator.rb b/app/models/spree/variant_decorator.rb
deleted file mode 100644
index 899149b7..00000000
--- a/app/models/spree/variant_decorator.rb
+++ /dev/null
@@ -1,7 +0,0 @@
-Spree::Variant.class_eval do
-
-  has_many :subscriptions, class_name: "Spree::Subscription", dependent: :restrict_with_error
-  delegate :variants_including_master, to: :product, prefix: true
-  alias_method :product_variants, :product_variants_including_master
-
-end
diff --git a/app/models/spree/line_item_decorator.rb b/app/models/spree_product_subscriptions/line_item_decorator.rb
similarity index 70%
rename from app/models/spree/line_item_decorator.rb
rename to app/models/spree_product_subscriptions/line_item_decorator.rb
index a0d24dfa..b478c4f3 100644
--- a/app/models/spree/line_item_decorator.rb
+++ b/app/models/spree_product_subscriptions/line_item_decorator.rb
@@ -1,11 +1,13 @@
-Spree::LineItem.class_eval do
+module SpreeProductSubscriptions::LineItemDecorator
 
-  attr_accessor :subscription_frequency_id, :delivery_number, :subscribe
 
-  after_create :create_subscription!, if: :subscribable?
-  after_update :update_subscription_quantity, if: :can_update_subscription_quantity?
-  after_update :update_subscription_attributes, if: :can_update_subscription_attributes?
-  after_destroy :destroy_associated_subscription!, if: :subscription?
+  def self.prepended(base)
+    base.after_create :create_subscription!, if: :subscribable?
+    base.after_update :update_subscription_quantity, if: :can_update_subscription_quantity?
+    base.after_update :update_subscription_attributes, if: :can_update_subscription_attributes?
+    base.after_destroy :destroy_associated_subscription!, if: :subscription?
+    base.attr_accessor :subscription_frequency_id, :delivery_number, :subscribe
+  end
 
   def subscription_attributes_present?
     subscription_frequency_id.present? || delivery_number.present?
@@ -67,3 +69,5 @@ def can_update_subscription_quantity?
     end
 
 end
+
+Spree::LineItem.prepend SpreeProductSubscriptions::LineItemDecorator
diff --git a/app/models/spree_product_subscriptions/order_decorator.rb b/app/models/spree_product_subscriptions/order_decorator.rb
new file mode 100644
index 00000000..80aa466d
--- /dev/null
+++ b/app/models/spree_product_subscriptions/order_decorator.rb
@@ -0,0 +1,40 @@
+module SpreeProductSubscriptions::OrderDecorator  
+
+  def self.prepended(base)
+    base.has_one :order_subscription, class_name: "Spree::OrderSubscription", dependent: :destroy
+    base.has_one :parent_subscription, through: :order_subscription, source: :subscription
+    base.has_many :subscriptions, class_name: "Spree::Subscription",
+                             foreign_key: :parent_order_id,
+                             dependent: :restrict_with_error
+    base.after_update :update_subscriptions
+    base.state_machine.after_transition to: :complete, do: :enable_subscriptions, if: :any_disabled_subscription?
+    base.alias_attribute :guest_token, :token
+  end
+
+  private
+
+    def enable_subscriptions
+      subscriptions.each do |subscription|
+        subscription.update(
+          source: payments.from_credit_card.first.source,
+          enabled: true,
+          ship_address: ship_address.clone,
+          bill_address: bill_address.clone
+        )
+      end
+    end
+
+    def any_disabled_subscription?
+      subscriptions.disabled.any?
+    end
+
+    def update_subscriptions
+      line_items.each do |line_item|
+        if line_item.subscription_attributes_present?
+          subscriptions.find_by(variant: line_item.variant).update(line_item.updatable_subscription_attributes)
+        end
+      end
+    end
+end
+
+Spree::Order.prepend SpreeProductSubscriptions::OrderDecorator
diff --git a/app/models/spree_product_subscriptions/product_decorator.rb b/app/models/spree_product_subscriptions/product_decorator.rb
new file mode 100644
index 00000000..2c79b4a8
--- /dev/null
+++ b/app/models/spree_product_subscriptions/product_decorator.rb
@@ -0,0 +1,15 @@
+module SpreeProductSubscriptions::ProductDecorator
+
+  def self.prepended(base)
+    base.has_many :subscriptions, through: :variants_including_master, source: :subscriptions, dependent: :restrict_with_error
+    base.has_many :product_subscription_frequencies, class_name: "Spree::ProductSubscriptionFrequency", dependent: :destroy
+    base.has_many :subscription_frequencies, through: :product_subscription_frequencies, dependent: :destroy
+    base.validates :subscription_frequencies, presence: true, if: :subscribable?
+    base.scope :subscribable, -> { where(subscribable: true) }
+    base.whitelisted_ransackable_attributes += %w( is_subscribable )  
+    base.alias_attribute :subscribable, :is_subscribable
+  end
+
+end
+
+Spree::Product.prepend SpreeProductSubscriptions::ProductDecorator
diff --git a/app/models/spree_product_subscriptions/variant_decorator.rb b/app/models/spree_product_subscriptions/variant_decorator.rb
new file mode 100644
index 00000000..a4d47ae0
--- /dev/null
+++ b/app/models/spree_product_subscriptions/variant_decorator.rb
@@ -0,0 +1,12 @@
+module SpreeProductSubscriptions::VariantDecorator
+
+
+  def self.prepended(base)
+    base.has_many :subscriptions, class_name: "Spree::Subscription", dependent: :restrict_with_error
+    base.delegate :variants_including_master, to: :product, prefix: true
+    base.alias_method :product_variants, :product_variants_including_master  
+  end
+
+end
+
+Spree::Variant.prepend SpreeProductSubscriptions::VariantDecorator
diff --git a/app/overrides/add_checkboxes_to_product_show_page.rb b/app/overrides/add_checkboxes_to_product_show_page.rb
index b9c7bc29..de43b6d3 100644
--- a/app/overrides/add_checkboxes_to_product_show_page.rb
+++ b/app/overrides/add_checkboxes_to_product_show_page.rb
@@ -1,6 +1,6 @@
 Deface::Override.new(
   virtual_path: "spree/products/_cart_form",
   name: "add_checkboxes_to_cart_form",
-  insert_before: ".add-to-cart",
+  insert_before: "erb[loud]:contains('hidden_field_tag')",
   partial: "spree/products/cart_checkboxes"
 )
diff --git a/app/overrides/add_class_to_add_to_cart_div_on_products_show_page.rb b/app/overrides/add_class_to_add_to_cart_div_on_products_show_page.rb
new file mode 100644
index 00000000..e69de29b
diff --git a/app/overrides/add_subscribable_fields_to_products_show_page.rb b/app/overrides/add_subscribable_fields_to_products_show_page.rb
index 49c7b389..566f9c73 100644
--- a/app/overrides/add_subscribable_fields_to_products_show_page.rb
+++ b/app/overrides/add_subscribable_fields_to_products_show_page.rb
@@ -1,6 +1,13 @@
+Deface::Override.new(
+  virtual_path: "spree/products/_cart_form",
+  name: "add_class_to_add_to_cart_div",
+  set_attributes: "#inside-product-cart-form div:nth-of-type(3)",
+  attributes: { class: 'add-to-cart' }
+)
+
 Deface::Override.new(
   virtual_path: "spree/products/_cart_form",
   name: "add_subscribable_fields_to_products_show",
-  insert_after: ".add-to-cart",
+  insert_after: "erb[loud]:contains('hidden_field_tag')",
   partial: "spree/products/subscription_fields"
 )
diff --git a/app/overrides/add_subscribed_field_in_cart_listing.rb b/app/overrides/add_subscribed_field_in_cart_listing.rb
index 515fd7e0..e79ced4a 100644
--- a/app/overrides/add_subscribed_field_in_cart_listing.rb
+++ b/app/overrides/add_subscribed_field_in_cart_listing.rb
@@ -1,7 +1,7 @@
 Deface::Override.new(
   virtual_path: "spree/orders/_line_item",
   name: "add_subscribed_field_to_cart_listing",
-  insert_bottom: ".line-item",
+  insert_bottom: ".shopping-cart-item",
   partial: "spree/orders/subscription_field"
 )
 
@@ -10,11 +10,4 @@
   name: "edit_header_in_cart_listing",
   insert_bottom: "[data-hook='cart_items_headers']",
   partial: "spree/orders/cart_subscription_header"
-)
-
-Deface::Override.new(
-  virtual_path: "spree/orders/_form",
-  name: "edit_footer_in_cart_listing",
-  insert_bottom: ".cart-total",
-  partial: "spree/orders/cart_subscription_footer"
-)
+)
\ No newline at end of file
diff --git a/app/overrides/add_subscription_number_to_order_page.rb b/app/overrides/add_subscription_number_to_order_page.rb
index b0b00837..a8e47126 100644
--- a/app/overrides/add_subscription_number_to_order_page.rb
+++ b/app/overrides/add_subscription_number_to_order_page.rb
@@ -1,6 +1,6 @@
 Deface::Override.new(
   virtual_path: 'spree/orders/show',
   name: 'add_subscription_number_to_order_page',
-  insert_after: "fieldset#order_summary h1",
+  insert_after: ".order-show-number",
   partial: 'spree/orders/subscription_number'
 )
diff --git a/app/overrides/add_subscriptions_admin_tab.rb b/app/overrides/add_subscriptions_admin_tab.rb
index daf9caac..d9441586 100644
--- a/app/overrides/add_subscriptions_admin_tab.rb
+++ b/app/overrides/add_subscriptions_admin_tab.rb
@@ -1,6 +1,6 @@
 Deface::Override.new(
-  virtual_path: 'spree/layouts/admin',
+  virtual_path: 'spree/admin/shared/_main_menu',
   name: 'subscriptions_admin_tab',
-  insert_bottom: '#main-sidebar',
+  insert_bottom: 'nav',
   partial: 'spree/admin/shared/subscriptions_sidebar_menu'
 )
diff --git a/app/views/spree/admin/products/_subscribable.html.erb b/app/views/spree/admin/products/_subscribable.html.erb
index 8d3ddccd..ce27e12a 100644
--- a/app/views/spree/admin/products/_subscribable.html.erb
+++ b/app/views/spree/admin/products/_subscribable.html.erb
@@ -5,7 +5,7 @@
     <%= f.error_message_on :subscribable %>
   <% end %>
 </div>
-<div id="subscribable_options" class=<%= @product.subscribable? ? '' : 'hidden' %>>
+<div id="subscribable_options" class='<%= @product.subscribable? ? "" : "is-hidden" %>'>
   <%= f.collection_check_boxes :subscription_frequency_ids, Spree::SubscriptionFrequency.all, :id, :title, { include_hidden: false } do |builder| %>
     <%= builder.label { builder.check_box(class: "subscribable-option") + builder.text } %>
     <br>
diff --git a/app/views/spree/orders/_cart_subscription_header.html.erb b/app/views/spree/orders/_cart_subscription_header.html.erb
index bc8f77b8..c7b9f9d4 100644
--- a/app/views/spree/orders/_cart_subscription_header.html.erb
+++ b/app/views/spree/orders/_cart_subscription_header.html.erb
@@ -1,2 +1,2 @@
-<th class='cart_item_subscription_header text-center'><%= Spree.t(:recurring_delivery_interval) %></th>
-<th class='cart_item_subscription_header text-center'><%= Spree.t(:total_deliveries) %></th>
+<div class='d-table-cell cart_item_subscription_header text-uppercase'><%= Spree.t(:recurring_delivery_interval) %></div>
+<div class='d-table-cell cart_item_subscription_header text-uppercase'><%= Spree.t(:total_deliveries) %></div>
diff --git a/app/views/spree/orders/_subscription_field.html.erb b/app/views/spree/orders/_subscription_field.html.erb
index d275e8ca..1c546f9b 100644
--- a/app/views/spree/orders/_subscription_field.html.erb
+++ b/app/views/spree/orders/_subscription_field.html.erb
@@ -1,15 +1,15 @@
 <% subscription = @order.subscriptions.find_by(variant: variant) %>
-<td class='cart-item-subscription text-center' data-hook='cart_item_subscription'>
+<div class='cart-item-subscription d-lg-table-cell' data-hook='cart_item_subscription'>
   <% if subscription %>
       <%= item_form.collection_select :subscription_frequency_id, variant.product.subscription_frequencies, :id, :title, { selected: subscription.subscription_frequency_id }, { class: "form-control" } %>
   <% else %>
     Not Subscribed
   <% end %>
-</td>
-<td class="text-center">
+</div>
+<div class="cart-item-subscription d-lg-table-cell">
   <% if subscription %>
     <%= item_form.number_field :delivery_number, class: "form-control", min: 1, value: subscription.delivery_number %>
   <% else %>
     None
   <% end %>
-</td>
+</div>
diff --git a/app/views/spree/products/_cart_checkboxes.html.erb b/app/views/spree/products/_cart_checkboxes.html.erb
index 579cbc00..58b9dc67 100644
--- a/app/views/spree/products/_cart_checkboxes.html.erb
+++ b/app/views/spree/products/_cart_checkboxes.html.erb
@@ -1,5 +1,5 @@
 <% if @product.subscribable? %>
-  <br><br>
+  <br><hr><br>
   <div id="cart_checkboxes" class="form-group">
     <%= radio_button_tag :cart, ".add-to-cart", true, class: "cart_radio_button" %>
     <%= label_tag "cart_.add-to-cart".to_s, Spree.t(:one_time_order), id: "cart_.add-to-cart" %>
diff --git a/app/views/spree/products/_subscription_fields.html.erb b/app/views/spree/products/_subscription_fields.html.erb
index 4bf8d90c..e0511502 100644
--- a/app/views/spree/products/_subscription_fields.html.erb
+++ b/app/views/spree/products/_subscription_fields.html.erb
@@ -1,6 +1,7 @@
 <% if @product.subscribable? %>
   <div class="subscription_options" style="display: none;">
-    <br><br>
+    <hr>
+    <br>
     <% subscription = Spree::Subscription.new %>
     <span>
       <%= label_tag :subscription, Spree.t(:recurring_delivery_interval) %><span class="required">*</span>
@@ -12,17 +13,6 @@
       <br>
       <%= number_field :subscription, :delivery_number, class: "form-control", min: 1, value: 1 %>
     </span>
-    <br>
-    <span>
-      <%= label_tag :subscription, Spree.t(:quantity) %><span class="required">*</span>
-      <br>
-      <%= number_field_tag :quantity, 1, class: 'title form-control', min: 1 %>
-    </span>
-    <br>
-    <span class='input-group-btn'>
-      <%= button_tag class: 'btn btn-success', id: 'subscribe-button', type: :submit, name: :subscribe, value: '1' do %>
-        <%= Spree.t(:subscribe_now) %>
-      <% end %>
-    </span>
   </div>
+  <br>
 <% end %>
diff --git a/app/views/spree/subscriptions/_subscription.html.erb b/app/views/spree/subscriptions/_subscription.html.erb
index 10514c75..d8b5c4d1 100644
--- a/app/views/spree/subscriptions/_subscription.html.erb
+++ b/app/views/spree/subscriptions/_subscription.html.erb
@@ -15,8 +15,8 @@
         Completed
     <% else %>
       <span id="pause_links"><%= render partial: 'spree/subscriptions/pause_links', locals: { btn_class: "btn-xs" } %></span>
-      <%= link_to Spree.t(:edit), edit_subscription_path(subscription), class: "btn btn-xs btn-default" %>
-      <%= link_to Spree.t("subsriptions.admin.cancel"), "javascript:void(0)", class: "btn ajax_handler btn-xs btn-danger", data: { method: "PATCH", confirmation: Spree.t("subscriptions.confirm.cancel"), url: cancel_subscription_path(subscription) } %>
+      <span><%= link_to Spree.t(:edit), edit_subscription_path(subscription), class: "btn btn-xs btn-primary" %></span>
+      <span><%= link_to Spree.t("subsriptions.admin.cancel"), "javascript:void(0)", class: "btn ajax_handler btn-xs btn-danger", data: { method: "PATCH", confirmation: Spree.t("subscriptions.confirm.cancel"), url: cancel_subscription_path(subscription) } %></span>
     <% end %>
   </td>
 </tr>
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 8321646b..4c22a2e3 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -5,6 +5,10 @@ en:
   hello: "Hello world"
 
   spree:
+    subscription_order: "Subscription Order"
+    recurring_delivery_interval: "Recurring Delivery Interval"
+    total_deliveries: "Total Deliveries"
+    subscribe_now: "Subscribe Now"
     subscription_notifier:
       notify_confirmation:
         subject: "%{frequency} %{number} Subscription Confirmation"
diff --git a/lib/spree_product_subscriptions/factories.rb b/lib/spree_product_subscriptions/factories.rb
index 501f6111..1fb548b2 100644
--- a/lib/spree_product_subscriptions/factories.rb
+++ b/lib/spree_product_subscriptions/factories.rb
@@ -1,16 +1,16 @@
 FactoryBot.define do
   factory :monthly_subscription_frequency, class: Spree::SubscriptionFrequency do
-    title "monthly"
-    months_count 1
+    title { "monthly" }
+    months_count  { 1 }
   end
 
   factory :nil_attributes_subscription, class: Spree::Subscription do
   end
 
   factory :valid_subscription, class: Spree::Subscription do
-    price 20.00
-    quantity 2
-    delivery_number 4
+    price { 20.00 }
+    quantity { 2 }
+    delivery_number { 4 }
     association :variant, factory: :base_variant
     association :frequency, factory: :monthly_subscription_frequency
     association :parent_order, factory: :completed_order_with_totals
diff --git a/spec/controllers/spree/admin/payments_controller_decorator_spec.rb b/spec/controllers/spree/admin/payments_controller_decorator_spec.rb
index 325f7172..08b3196b 100644
--- a/spec/controllers/spree/admin/payments_controller_decorator_spec.rb
+++ b/spec/controllers/spree/admin/payments_controller_decorator_spec.rb
@@ -8,7 +8,7 @@
   stub_authorization!
 
   def do_new
-    spree_get :new, order_id: order.number
+    get :new, params: { order_id: order.number }
   end
 
   describe "method overrides" do
diff --git a/spec/controllers/spree/admin/subscriptions_controller_spec.rb b/spec/controllers/spree/admin/subscriptions_controller_spec.rb
index a174dcbc..342ebf75 100644
--- a/spec/controllers/spree/admin/subscriptions_controller_spec.rb
+++ b/spec/controllers/spree/admin/subscriptions_controller_spec.rb
@@ -9,7 +9,7 @@
 
   describe "#cancellation" do
     def do_cancellation params
-      spree_get :cancellation, params
+      get :cancellation, params: params
     end
 
     let(:params) { { id: active_subscription.id } }
@@ -34,7 +34,7 @@ def do_cancellation params
 
   describe "pause" do
     def do_pause
-      spree_post :pause, format: :json, id: active_subscription.id
+      post :pause, params: { format: :json, id: active_subscription.id }
     end
 
     before do
@@ -83,7 +83,7 @@ def do_pause
 
   describe "unpause" do
     def do_unpause
-      spree_post :unpause, format: :json, id: active_subscription.id
+      post :unpause, params: { format: :json, id: active_subscription.id }
     end
 
     before do
@@ -131,7 +131,7 @@ def do_unpause
   end
 
   def do_cancel params
-    spree_post :cancel, params
+    post :cancel, params: params
   end
 
   describe "#Cancel" do
@@ -192,7 +192,7 @@ def do_cancel params
   describe "callbacks" do
     describe "#ensure_not_cancelled" do
       def do_cancellation params
-        spree_get :cancellation, params
+        get :cancellation, params: params
       end
 
       context "when subscription is cancelled" do
@@ -242,7 +242,7 @@ def do_cancellation params
 
     describe "#collection" do
       def do_index
-        spree_get :index
+        get :index
       end
 
       let(:subscriptions) { double(ActiveRecord::Relation) }
diff --git a/spec/controllers/spree/orders_controller_decorator_spec.rb b/spec/controllers/spree/orders_controller_decorator_spec.rb
index 1d714fe6..fb9461f2 100644
--- a/spec/controllers/spree/orders_controller_decorator_spec.rb
+++ b/spec/controllers/spree/orders_controller_decorator_spec.rb
@@ -4,26 +4,10 @@
 
   stub_authorization!
 
-  describe "Callbacks" do
-    describe "#add_subscription_fields" do
-      def do_populate params
-        spree_post :populate, params
-      end
-
-      let(:variant) { create(:variant) }
-      let (:with_subscribe_params) { { subscribe: true, variant_id: variant.id, subscription: { subscription_frequency_id: 1, delivery_number: 6 } }.with_indifferent_access }
-
-      context "send populate request with params[:subscribe] present" do
-        before { do_populate with_subscribe_params }
-        it { expect(controller.send :add_subscription_fields).to_not be_nil }
-      end
-    end
-  end
-
   describe "Callbacks" do
     describe "#restrict_guest_subscription" do
       def do_update params
-        spree_put :update, params
+        put :update, params: params
       end
 
       let (:order) { mock_model(Spree::Order) }
diff --git a/spec/controllers/spree/subscriptions_controller_spec.rb b/spec/controllers/spree/subscriptions_controller_spec.rb
index 5bd2e4bb..d88c4d62 100644
--- a/spec/controllers/spree/subscriptions_controller_spec.rb
+++ b/spec/controllers/spree/subscriptions_controller_spec.rb
@@ -10,7 +10,7 @@
 
   describe "Callbacks" do
     def do_cancel params
-      spree_post :cancel, params
+      post :cancel, params: params
     end
 
     describe "#ensure_subscription" do
@@ -219,7 +219,7 @@ def do_cancel params
 
   describe "edit" do
     def do_edit params
-      spree_get :edit, params
+      get :edit, params: params
     end
 
     it { is_expected.to use_before_action(:ensure_subscription_belongs_to_user) }
@@ -278,7 +278,7 @@ def do_edit params
 
   describe "update" do
     def do_update params
-      spree_put :update, params
+      put :update, params: params
     end
 
     describe "when subscription is found" do
@@ -374,7 +374,7 @@ def do_update params
 
   describe "pause" do
     def do_pause
-      spree_post :pause, format: :json, id: active_subscription.id
+      post :pause, params: { format: :json, id: active_subscription.id }
     end
 
     before do
@@ -426,7 +426,7 @@ def do_pause
 
   describe "unpause" do
     def do_unpause
-      spree_post :unpause, format: :json, id: active_subscription.id
+      post :unpause, params: { format: :json, id: active_subscription.id }
     end
 
     before do
@@ -479,7 +479,7 @@ def do_unpause
   describe "cancel" do
     describe "html response" do
       def do_cancel params
-        spree_post :cancel, params
+        post :cancel, params: params
       end
 
       before do
@@ -533,7 +533,7 @@ def do_cancel params
 
     describe "json response" do
       def do_cancel
-        spree_post :cancel, format: :json, id: active_subscription.id
+        post :cancel, params: { format: :json, id: active_subscription.id }
       end
 
       before do
diff --git a/spec/controllers/spree/users_controller_decorator_spec.rb b/spec/controllers/spree/users_controller_decorator_spec.rb
index c1ce0519..bc477e40 100644
--- a/spec/controllers/spree/users_controller_decorator_spec.rb
+++ b/spec/controllers/spree/users_controller_decorator_spec.rb
@@ -7,7 +7,7 @@
   describe "Callbacks" do
     describe "#load_subscriptions" do
       def do_show
-        spree_get :show
+        get :show
       end
 
       let(:orders) { double(ActiveRecord::Relation) }
diff --git a/spec/models/spree/subscription_spec.rb b/spec/models/spree/subscription_spec.rb
index fbb254c5..dd930a73 100644
--- a/spec/models/spree/subscription_spec.rb
+++ b/spec/models/spree/subscription_spec.rb
@@ -440,7 +440,7 @@
     context "#order_attributes" do
       it { expect(active_subscription.send :order_attributes).to eq ({
         currency: order.currency,
-        guest_token: order.guest_token,
+        token: order.token,
         store: order.store,
         user: order.user,
         created_by: order.user,
@@ -451,7 +451,7 @@
     context "#order recreation" do
       let(:order_attributes) { {
         currency: order.currency,
-        guest_token: order.guest_token,
+        token: order.token,
         store: order.store,
         user: order.user,
         created_by: order.user,
@@ -472,7 +472,7 @@
 
       context "#make_new_order" do
         it { expect(created_order.currency).to eq new_order.currency }
-        it { expect(created_order.guest_token).to eq new_order.guest_token }
+        it { expect(created_order.token).to eq new_order.token }
         it { expect(created_order.store).to eq new_order.store }
         it { expect(created_order.user).to eq new_order.user }
         it { expect(created_order.created_by).to eq new_order.created_by }
diff --git a/spec/models/spree/variant_decorator_spec.rb b/spec/models/spree/variant_decorator_spec.rb
index 512ddbc9..eeb6e8cc 100644
--- a/spec/models/spree/variant_decorator_spec.rb
+++ b/spec/models/spree/variant_decorator_spec.rb
@@ -11,7 +11,7 @@
   end
 
   describe 'alias method' do
-    it { expect(Spree::Variant.instance_method(:product_variants_including_master)).to eq Spree::Variant.instance_method(:product_variants) }
+    it { expect(Spree::Variant.instance_method(:product_variants).original_name).to eq(:product_variants_including_master) }
   end
 
 end
diff --git a/spree_product_subscriptions.gemspec b/spree_product_subscriptions.gemspec
index f5af6b10..90e6b24f 100644
--- a/spree_product_subscriptions.gemspec
+++ b/spree_product_subscriptions.gemspec
@@ -16,7 +16,7 @@ Gem::Specification.new do |s|
   s.require_path = 'lib'
   s.requirements << 'none'
 
-  s.add_dependency 'spree_core', '>= 3.2.0' , '< 4.0'
+  s.add_dependency 'spree_core', '>= 4.0.0'
 
   s.add_development_dependency 'capybara', '~> 2.4'
   s.add_development_dependency 'coffee-rails', '~> 4.2'
@@ -24,13 +24,14 @@ Gem::Specification.new do |s|
   s.add_development_dependency 'factory_bot'
   s.add_development_dependency 'ffaker'
   s.add_development_dependency 'pry-rails', '~> 0.3.4'
-  s.add_development_dependency 'rspec-rails',  '~> 3.4'
+  s.add_development_dependency 'rspec-rails',  '~> 4.0'
   s.add_development_dependency 'rspec-activemodel-mocks', '~> 1.0.3'
   s.add_development_dependency 'sass-rails', '~> 5.0.1'
   s.add_development_dependency 'selenium-webdriver', '~> 2.52.0'
   s.add_development_dependency 'shoulda-matchers', '~> 3.1.1'
   s.add_development_dependency 'shoulda-callback-matchers', '~> 1.1.3'
   s.add_development_dependency 'simplecov', '~> 0.11.2'
-  s.add_development_dependency 'sqlite3', '~> 1.3.11'
+  s.add_development_dependency 'sqlite3', '~> 1.4'
   s.add_development_dependency 'appraisal'
+  s.add_development_dependency 'deface', '~> 1.0'
 end