Start release notes for v2.16.4

Change-Id: If52e17a0623a5c7cf8a44fd6deecbab04b9f4746
diff --git a/pages/site/releases/2.16.md b/pages/site/releases/2.16.md
index fd4f67e..4e491bd 100644
--- a/pages/site/releases/2.16.md
+++ b/pages/site/releases/2.16.md
@@ -488,6 +488,54 @@
 
 ## Bugfix Releases
 
+### 2.16.4
+
+#### PolyGerrit
+
+* [Issue 9909](https://bugs.chromium.org/p/gerrit/issues/detail?id=9909):
+  Do not crash PolyGerrit UI if permitted labels array is empty
+
+* [Issue 10324](https://bugs.chromium.org/p/gerrit/issues/detail?id=10324):
+  Allow plugins (e.g. delete-project) to control the cache invalidation
+  and display new content immediately without refreshing the page.
+
+* Fix broken links in gr-icons.html.
+
+* [Issue 7669](https://bugs.chromium.org/p/gerrit/issues/detail?id=7669),
+  [Issue 9614](https://bugs.chromium.org/p/gerrit/issues/detail?id=9614):
+  Fix '/' getting typed in search bar when pressed.
+
+* [Issue 10151](https://bugs.chromium.org/p/gerrit/issues/detail?id=10151):
+  [Issue 10019](https://bugs.chromium.org/p/gerrit/issues/detail?id=10019):
+  Fix the "delete" button visibility to allow branch deletion.
+
+* [Issue 10317](https://bugs.chromium.org/p/gerrit/issues/detail?id=10317):
+  Don't show "Same Topic" for only one change.
+
+  When there is only one change in the topic, it doesn't add any value
+  to show the "Same Topic" tab/section because it will always only include
+  the currently viewed change.
+
+  The query used to get the changes is modified to exclude the current
+  change. This means that the "Same Topic" tab/section now only shows other
+  changes in the same topic, but never the current change.
+
+* Create the `.git/hooks` folder in download commands.
+
+#### Other fixes
+
+* Add method to get related changes in the Changes API.
+
+* Add method to get edit details in the Change Edit API.
+
+  The new method allows to set the base revision, and request to include the
+  files and download commands.
+
+* Add `--skip-project` option to the `MigrateToNoteDb` command.
+
+  This is useful when only a few projects should be skipped but all others
+  should be migrated.
+
 ### 2.16.3
 
 * [Issue 10262](https://bugs.chromium.org/p/gerrit/issues/detail?id=10262):