diff --git a/CHANGES b/CHANGES
index 375dea546f..33f05c95c6 100644
--- a/CHANGES
+++ b/CHANGES
@@ -952,7 +952,9 @@
 			when the resent query's result was SERVFAIL. [GL #3020]
 
 5830.	[func]		Implement incremental resizing of isc_ht hash tables to
-			perform the rehashing gradually. [GL #3212]
+			perform the rehashing gradually. The catalog zone
+			implementation has been optimized to work with hundreds
+			of thousands of member zones. [GL #3212] [GL #3744]
 
 5829.	[func]		Refactor and simplify isc_timer API in preparation
 			for further refactoring on top of network manager
diff --git a/doc/notes/notes-9.19.0.rst b/doc/notes/notes-9.19.0.rst
index a6f92bfe48..f6363e680c 100644
--- a/doc/notes/notes-9.19.0.rst
+++ b/doc/notes/notes-9.19.0.rst
@@ -56,3 +56,6 @@ Feature Changes
   threads. This should increase the responsiveness of :iscman:`named`
   when RPZ updates are being applied after an RPZ zone has been
   successfully transferred. :gl:`#3190`
+
+- The catalog zone implementation has been optimized to work with
+  hundreds of thousands of member zones. :gl:`#3212` :gl:`#3744`