1 files changed, 13 insertions, 0 deletions
diff --git a/actionpack/CHANGELOG.md b/actionpack/CHANGELOG.md
index 73a833a23b..bffe9a85a8 100644
--- a/actionpack/CHANGELOG.md
+++ b/actionpack/CHANGELOG.md
@@ -1,3 +1,16 @@
+*   Accessing mime types via constants like `Mime::HTML` is deprecated.  Please
+    change code like this:
+
+      Mime::HTML
+
+    To this:
+
+      Mime::Types[:HTML]
+
+    This change is so that Rails will not manage a list of constants, and fixes
+    an issue where if a type isn't registered you could possibly get the wrong
+    object.
+
 *   `url_for` does not modify its arguments when generating polymorphic URLs.
 
     *Bernerd Schaefer*