diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index 90cf71521a..97df382bb1 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,3 +1,8 @@
+*   Use advisory locking to raise a ConcurrentMigrationError instead of
+    attempting to migrate when another migration is currently running.
+
+    *Sam Davies*
+
 *   Added `ActiveRecord::Relation#left_outer_joins`.
 
     Example: