diff --git a/README.md b/README.md
index cf5bac0..456733d 100644
--- a/README.md
+++ b/README.md
@@ -9,6 +9,10 @@ Try Spree Admin Roles and Access for Spree master with direct deployment on Hero
 
 [![Deploy](https://www.herokucdn.com/deploy/button.svg)](https://heroku.com/deploy?template=https://github.com/vinsol-spree-contrib/spree-demo-heroku/tree/spree-admin-roles-and-access-master)
 
+Try Spree Admin Roles and Access for Spree 4-1 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-admin-roles-and-access-4-1)
+
 Try Spree Admin Roles and Access 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-admin-roles-and-access-3-4)
diff --git a/app/controllers/spree/admin/base_controller_decorator.rb b/app/controllers/spree/admin/base_controller_decorator.rb
deleted file mode 100644
index 990928f..0000000
--- a/app/controllers/spree/admin/base_controller_decorator.rb
+++ /dev/null
@@ -1,27 +0,0 @@
-Spree::Admin::BaseController.class_eval do
-  def authorize_admin
-    begin
-      if params[:id]
-        record = model_class.where(PARAM_ATTRIBUTE[controller_name] => params[:id]).first
-      elsif new_action?
-        record = model_class.new
-      else
-        record = model_class
-      end
-      raise if record.blank?
-    rescue
-      record = "#{params[:controller]}"
-    end
-    authorize! :admin, record
-    authorize_with_attributes! params[:action].to_sym, record, params[controller_name.singularize]
-  end
-
-  private
-    def unauthorized
-      redirect_unauthorized_access
-    end
-
-    def new_action?
-      NEW_ACTIONS.include?(params[:action].to_sym)
-    end
-end
diff --git a/app/models/spree/role_decorator.rb b/app/models/spree/role_decorator.rb
deleted file mode 100644
index bb1f04a..0000000
--- a/app/models/spree/role_decorator.rb
+++ /dev/null
@@ -1,18 +0,0 @@
-Spree::Role.class_eval do
-
-  has_many :roles_permission_sets, dependent: :destroy
-  has_many :permission_sets, through: :roles_permission_sets
-  has_many :permissions, through: :permission_sets
-
-  # DEPRECATED: Use permission sets instead. Only here for aiding migration for existing users
-  has_and_belongs_to_many :legacy_permissions, join_table: 'spree_roles_permissions', class_name: 'Spree::Permission'
-
-  validates :name, uniqueness: true, allow_blank: true
-  validates :permission_sets, length: { minimum: 1, too_short: :atleast_one_permission_set_is_required }, on: :update
-
-  def has_permission?(permission_title)
-    permissions.pluck(:title).include?(permission_title)
-  end
-
-  scope :default_role, lambda { where(is_default: true) }
-end
diff --git a/app/models/spree/user_decorator.rb b/app/models/spree/user_decorator.rb
deleted file mode 100644
index 35b09e7..0000000
--- a/app/models/spree/user_decorator.rb
+++ /dev/null
@@ -1,5 +0,0 @@
-module Spree
-  Spree.user_class.class_eval do
-    alias_attribute :roles, :spree_roles
-  end
-end
diff --git a/app/models/spree/ability_decorator.rb b/app/models/spree_admin_roles_and_access/ability_decorator.rb
similarity index 80%
rename from app/models/spree/ability_decorator.rb
rename to app/models/spree_admin_roles_and_access/ability_decorator.rb
index 52e9ef7..6fbd346 100644
--- a/app/models/spree/ability_decorator.rb
+++ b/app/models/spree_admin_roles_and_access/ability_decorator.rb
@@ -1,6 +1,5 @@
-module Spree
-  Ability.class_eval do
-
+module SpreeAdminRolesAndAccess
+  module AbilityDecorator
     def initialize(user)
       self.clear_aliased_actions
 
@@ -15,7 +14,7 @@ def initialize(user)
 
       user_roles(user).map(&:permissions).flatten.uniq.map { |permission| permission.ability(self, user) }
 
-      Ability.abilities.each do |clazz|
+      ::Spree::Ability.abilities.each do |clazz|
         ability = clazz.send(:new, user)
         @rules = rules + ability.send(:rules)
       end
@@ -26,3 +25,5 @@ def user_roles(user)
     end
   end
 end
+
+Spree::Ability.prepend SpreeAdminRolesAndAccess::AbilityDecorator
\ No newline at end of file
diff --git a/app/models/spree_admin_roles_and_access/role_decorator.rb b/app/models/spree_admin_roles_and_access/role_decorator.rb
new file mode 100644
index 0000000..aa78101
--- /dev/null
+++ b/app/models/spree_admin_roles_and_access/role_decorator.rb
@@ -0,0 +1,24 @@
+module SpreeAdminRolesAndAccess
+  module RoleDecorator
+
+    def self.prepended(base)
+      base.has_many :roles_permission_sets, dependent: :destroy
+      base.has_many :permission_sets, through: :roles_permission_sets
+      base.has_many :permissions, through: :permission_sets
+
+      # DEPRECATED: Use permission sets instead. Only here for aiding migration for existing users
+      base.has_and_belongs_to_many :legacy_permissions, join_table: 'spree_roles_permissions', class_name: 'Spree::Permission'
+
+      base.validates :name, uniqueness: true, allow_blank: true
+      base.validates :permission_sets, length: { minimum: 1, too_short: :atleast_one_permission_set_is_required }, on: :update
+      base.scope :default_role, lambda { where(is_default: true) }
+    end
+
+    def has_permission?(permission_title)
+      permissions.pluck(:title).include?(permission_title)
+    end
+
+  end
+end
+
+Spree::Role.prepend SpreeAdminRolesAndAccess::RoleDecorator
\ No newline at end of file
diff --git a/app/models/spree_admin_roles_and_access/user_decorator.rb b/app/models/spree_admin_roles_and_access/user_decorator.rb
new file mode 100644
index 0000000..af5196e
--- /dev/null
+++ b/app/models/spree_admin_roles_and_access/user_decorator.rb
@@ -0,0 +1,9 @@
+module SpreeAdminRolesAndAccess
+  module UserDecorator
+    def self.prepended(base)
+      base.alias_attribute :roles, :spree_roles
+    end
+  end
+end
+
+Spree.user_class.prepend SpreeAdminRolesAndAccess::UserDecorator
\ No newline at end of file
diff --git a/lib/controllers/backend/spree/admin/base_controller_decorator.rb b/lib/controllers/backend/spree/admin/base_controller_decorator.rb
new file mode 100644
index 0000000..848b4d6
--- /dev/null
+++ b/lib/controllers/backend/spree/admin/base_controller_decorator.rb
@@ -0,0 +1,29 @@
+module Spree::Admin
+  module BaseControllerDecorator
+    def authorize_admin
+      begin
+        if params[:id]
+          record = model_class.where(PARAM_ATTRIBUTE[controller_name] => params[:id]).first
+        elsif new_action?
+          record = model_class.new
+        else
+          record = model_class
+        end
+        raise if record.blank?
+      rescue
+        record = "#{params[:controller]}"
+      end
+      authorize! :admin, record
+      authorize_with_attributes! params[:action].to_sym, record, params[controller_name.singularize]
+    end
+
+    private
+      def unauthorized
+        redirect_unauthorized_access
+      end
+
+      def new_action?
+        NEW_ACTIONS.include?(params[:action].to_sym)
+      end
+  end
+Spree::Admin::BaseController.prepend Spree::Admin::BaseControllerDecorator
\ No newline at end of file
diff --git a/lib/spree/permissions.rb b/lib/spree/permissions.rb
index f214d75..7c2223f 100644
--- a/lib/spree/permissions.rb
+++ b/lib/spree/permissions.rb
@@ -25,11 +25,11 @@ def method_missing(name, *args, &block)
       current_ability.can :create, Spree::Order
 
       current_ability.can :read, Spree::Order, [] do |order, token|
-        order.user == user || (order.guest_token && token == order.guest_token)
+        order.user == user || (order.token && token == order.token)
       end
 
       current_ability.can :update, Spree::Order do |order, token|
-        !order.completed? && (order.user == user || order.guest_token && token == order.guest_token)
+        !order.completed? && (order.user == user || order.token && token == order.token)
       end
 
       current_ability.can :read, Spree::Address do |address|
diff --git a/spec/models/spree/ability_decorator_spec.rb b/spec/models/spree/ability_decorator_spec.rb
index fd78816..6834063 100644
--- a/spec/models/spree/ability_decorator_spec.rb
+++ b/spec/models/spree/ability_decorator_spec.rb
@@ -26,7 +26,7 @@
   let(:permission17) { Spree::Permission.create(title: 'can-create-spree/products', priority: 3) }
   let(:permission_set) { Spree::PermissionSet.create!(name: 'test') }
 
-  let(:user) { Spree::User.create!(email: 'abc@test.com', password: '123456') }
+  let(:user) { Spree.user_class.create!(email: 'abc@test.com', password: '123456') }
   let(:role) { Spree::Role.where(name: 'user').first_or_create! }
   let(:roles) { [role] }
 
@@ -125,8 +125,8 @@
       it_should_behave_like 'access denied'
       it_should_behave_like 'no index allowed'
       it_should_behave_like 'default admin permissions'
-      it { expect(new_ability).to_not be_able_to :create, Spree::User, :role_ids }
-      it { expect(new_ability).to_not be_able_to :update, Spree::User, :role_ids }
+      it { expect(new_ability).to_not be_able_to :create, Spree.user_class, :role_ids }
+      it { expect(new_ability).to_not be_able_to :update, Spree.user_class, :role_ids }
     end
 
     context 'with warehouse_admin user' do
@@ -166,11 +166,11 @@
     let(:resource) { Object.new }
     let(:resource_shipment) { Spree::Shipment.new }
     let(:resource_product) { Spree::Product.new }
-    let(:resource_user) { Spree::User.new }
+    let(:resource_user) { Spree.user_class.new }
     let(:resource_order) { Spree::Order.new }
-    let(:fakedispatch_user) { Spree::User.new }
+    let(:fakedispatch_user) { Spree.user_class.new }
     let(:admin_role) { Spree::Role.where(name: 'admin').first_or_create! }
-    let(:user1) { Spree::User.new }
+    let(:user1) { Spree.user_class.new }
     let(:ability) { Spree::Ability.new(user) }
 
     context 'with admin user' do
@@ -262,7 +262,7 @@
       it_should_behave_like 'access granted'
     end
     context 'requested by other user' do
-      let(:resource) { Spree::User.new }
+      let(:resource) { Spree.user_class.new }
       it_should_behave_like 'create only'
     end
   end
@@ -276,7 +276,7 @@
     end
 
     context 'requested by other user' do
-      before(:each) { resource.user = Spree::User.new }
+      before(:each) { resource.user = Spree.user_class.new }
       it_should_behave_like 'create only'
     end
 
@@ -325,12 +325,12 @@
     end
 
     it 'should receive new on Spree::User when there is no user passed' do
-      expect(Spree::User).to receive(:new).and_return(user)
+      expect(Spree.user_class).to receive(:new).and_return(user)
       Spree::Ability.new(nil)
     end
 
     it 'should not receive new on Spree::User when there is no user passed' do
-      expect(Spree::User).to_not receive(:new)
+      expect(Spree.user_class).to_not receive(:new)
       Spree::Ability.new(user)
     end
 
@@ -359,10 +359,10 @@
 
       subject { ability }
 
-      it { expect(subject).to be_able_to :create, Spree::User.new }
-      it { expect(subject).to be_able_to :update, Spree::User.new }
-      it { expect(subject).to_not be_able_to :create, Spree::User.new, :role_ids }
-      it { expect(subject).to_not be_able_to :update, Spree::User.new, :role_ids }
+      it { expect(subject).to be_able_to :create, Spree.user_class.new }
+      it { expect(subject).to be_able_to :update, Spree.user_class.new }
+      it { expect(subject).to_not be_able_to :create, Spree.user_class.new, :role_ids }
+      it { expect(subject).to_not be_able_to :update, Spree.user_class.new, :role_ids }
     end
   end
 
diff --git a/spree_admin_roles_and_access.gemspec b/spree_admin_roles_and_access.gemspec
index 3cc1032..1e38374 100644
--- a/spree_admin_roles_and_access.gemspec
+++ b/spree_admin_roles_and_access.gemspec
@@ -14,14 +14,14 @@ Gem::Specification.new do |s|
   s.require_path = 'lib'
   s.requirements << 'none'
 
-  spree_version = '>= 3.2.0', '< 4.0.0'
+  spree_version = '>= 4.0.0'
 
   s.add_dependency 'spree_core', spree_version
   s.add_dependency 'spree_auth_devise'
 
   s.add_development_dependency 'capybara'
   s.add_development_dependency 'ffaker'
-  s.add_development_dependency 'rspec-rails', '~> 3.5.0'
+  s.add_development_dependency 'rspec-rails', '~> 4.0.0'
   s.add_development_dependency 'shoulda-matchers', '~> 3.1'
   s.add_development_dependency 'rspec-activemodel-mocks'
   s.add_development_dependency 'rails-controller-testing'