diff --git a/HISTORY b/HISTORY
index 5aff447b..10d6b98b 100644
--- a/HISTORY
+++ b/HISTORY
@@ -4,6 +4,7 @@
         repmgr: add option --verify-backup to "standby clone" (Ian)
         repmgrd: add additional optional parameters to "failover_validation command"
           (spaskalev; GitHub #651)
+        general: remove support for PostgreSQL 9.3 (Ian)
 
 5.1.0   2020-04-13
         repmgr: remove BDR 2.x support
diff --git a/doc/appendix-release-notes.xml b/doc/appendix-release-notes.xml
index 95c97e2d..975dd34d 100644
--- a/doc/appendix-release-notes.xml
+++ b/doc/appendix-release-notes.xml
@@ -24,6 +24,10 @@
     <para>
       &repmgr; 5.2.0 is a major release.
     </para>
+    <para>
+      This release removes support for PostgreSQL 9.3, which was
+      <ulink url="https://www.postgresql.org/docs/9.3/release-9-3-25.html">designated EOL in November 2018</ulink>.
+    </para>
 
     <sect2>
       <title>General improvements</title>