diff --git a/CHANGES b/CHANGES
index 2ad5684af7..a041b0d5ac 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,8 @@
+5371.	[bug]		Improve incremental updates of the RPZ summary
+			database to reduce delays that could occur when
+			a policy zone update included a large number of
+			record deletions. [GL #1447]
+
 5370.	[bug]		Deactivation of a netmgr handle associated with a
 			socket could be skipped in some circumstances.
 			Fixed by deactivating the netmgr handle before
diff --git a/doc/arm/notes-9.17.1.xml b/doc/arm/notes-9.17.1.xml
index 4c33ea316d..1e6c5a28b2 100644
--- a/doc/arm/notes-9.17.1.xml
+++ b/doc/arm/notes-9.17.1.xml
@@ -55,7 +55,12 @@
     <itemizedlist>
       <listitem>
         <para>
-	  None.
+	  When an RPZ policy zone was updated via zone transfer
+	  and a large number of records were deleted, <command>named</command>
+	  could become nonresponsive for a short period while deleted
+	  names were removed from the RPZ summary database. This database
+	  cleanup is now done incrementally over a longer period of time,
+	  reducing such delays. [GL #1447]
         </para>
       </listitem>
     </itemizedlist>