diff --git a/activemodel/lib/active_model/errors.rb b/activemodel/lib/active_model/errors.rb
index a2bb8f9977..b219914aee 100644
--- a/activemodel/lib/active_model/errors.rb
+++ b/activemodel/lib/active_model/errors.rb
@@ -305,7 +305,7 @@ module ActiveModel
 
     def to_h
       ActiveSupport::Deprecation.warn(<<~EOM)
-        ActiveModel::Errors#to_h is deprecated and will be removed in Rails 6.2
+        ActiveModel::Errors#to_h is deprecated and will be removed in Rails 6.2.
         Please use `ActiveModel::Errors.to_hash` instead. The values in the hash
         returned by `ActiveModel::Errors.to_hash` is an array of error messages.
       EOM