diff --git a/Changes.md b/Changes.md
index 69f33028..8199fa7a 100644
--- a/Changes.md
+++ b/Changes.md
@@ -1,3 +1,8 @@
+HEAD
+-----------
+
+- Undeprecate delay extension for ActionMailer 4.2+ . [#2186]
+
 3.3.2
 -----------
 
diff --git a/lib/sidekiq/extensions/action_mailer.rb b/lib/sidekiq/extensions/action_mailer.rb
index 77fb77a8..34de4d34 100644
--- a/lib/sidekiq/extensions/action_mailer.rb
+++ b/lib/sidekiq/extensions/action_mailer.rb
@@ -28,7 +28,6 @@ module Sidekiq
 
       def deliver(msg)
         if msg.respond_to?(:deliver_now)
-          ActiveSupport::Deprecation.warn('`ActionMailer.delay.method` is deprecated. Use `ActionMailer.method.deliver_later` instead and configure ActiveJob to use Sidekiq.')
           # Rails 4.2/5.0
           msg.deliver_now
         else