diff --git a/Gemfile b/Gemfile
index d9294841..2666f304 100644
--- a/Gemfile
+++ b/Gemfile
@@ -28,10 +28,5 @@ gem 'simple_enum'
 gem 'uuidtools'
 gem 'dalli'
 
-# Redmine extensions
-unless %w(easyproject easy_gantt).any? { |plugin| Dir.exist?(File.expand_path("../../#{plugin}", __FILE__)) }
-  gem 'redmine_extensions', '~> 0.2.5'
-end
-
 # Dav4Rack
 gem 'ox'
diff --git a/lib/redmine_dmsf/patches/attachable_patch.rb b/lib/redmine_dmsf/patches/attachable_patch.rb
index 94e6fed4..51da3e1a 100644
--- a/lib/redmine_dmsf/patches/attachable_patch.rb
+++ b/lib/redmine_dmsf/patches/attachable_patch.rb
@@ -34,4 +34,4 @@ module RedmineDmsf
 end
 
 RedmineExtensions::PatchManager.register_helper_patch 'Redmine::Acts::Attachable::InstanceMethods',
-  'RedmineDmsf::Patches::AttachablePatch', prepend: true
+    'RedmineDmsf::Patches::AttachablePatch', prepend: true
\ No newline at end of file
diff --git a/lib/redmine_dmsf/patches/custom_fields_helper_patch.rb b/lib/redmine_dmsf/patches/custom_fields_helper_patch.rb
index 71825477..e74c32a0 100644
--- a/lib/redmine_dmsf/patches/custom_fields_helper_patch.rb
+++ b/lib/redmine_dmsf/patches/custom_fields_helper_patch.rb
@@ -47,5 +47,9 @@ module RedmineDmsf
   end
 end
 
-RedmineExtensions::PatchManager.register_helper_patch 'CustomFieldsHelper',
-  'RedmineDmsf::Patches::CustomFieldsHelperPatch', prepend: true
+if defined?(EasyExtensions)
+  RedmineExtensions::PatchManager.register_helper_patch 'CustomFieldsHelper',
+    'RedmineDmsf::Patches::CustomFieldsHelperPatch', prepend: true
+else
+  CustomFieldsHelper.send(:prepend, RedmineDmsf::Patches::CustomFieldsHelperPatch)
+end
diff --git a/lib/redmine_dmsf/patches/project_patch.rb b/lib/redmine_dmsf/patches/project_patch.rb
index e84ba442..003e429c 100644
--- a/lib/redmine_dmsf/patches/project_patch.rb
+++ b/lib/redmine_dmsf/patches/project_patch.rb
@@ -115,5 +115,9 @@ module RedmineDmsf
   end
 end
 
-RedmineExtensions::PatchManager.register_model_patch 'Project',
-  'RedmineDmsf::Patches::ProjectPatch', prepend: true
+if defined?(EasyExtensions)
+  RedmineExtensions::PatchManager.register_model_patch 'Project',
+    'RedmineDmsf::Patches::ProjectPatch', prepend: true
+else
+  Project.send(:prepend, RedmineDmsf::Patches::ProjectPatch)
+end
diff --git a/lib/redmine_dmsf/patches/project_tabs_extended.rb b/lib/redmine_dmsf/patches/project_tabs_extended.rb
index b0c1ba80..96108cc8 100644
--- a/lib/redmine_dmsf/patches/project_tabs_extended.rb
+++ b/lib/redmine_dmsf/patches/project_tabs_extended.rb
@@ -41,5 +41,9 @@ module RedmineDmsf
   end
 end
 
-RedmineExtensions::PatchManager.register_helper_patch 'ProjectsHelper',
-  'RedmineDmsf::Patches::ProjectTabsExtended', prepend: true
+if defined?(EasyExtensions)
+  RedmineExtensions::PatchManager.register_helper_patch 'ProjectsHelper',
+    'RedmineDmsf::Patches::ProjectTabsExtended', prepend: true
+else
+  ProjectsHelper.send(:prepend, RedmineDmsf::Patches::ProjectTabsExtended)
+end
\ No newline at end of file