diff --git a/nixos/doc/manual/from_md/release-notes/rl-2211.section.xml b/nixos/doc/manual/from_md/release-notes/rl-2211.section.xml
index 55c20427cfde..b0a84de57e0b 100644
--- a/nixos/doc/manual/from_md/release-notes/rl-2211.section.xml
+++ b/nixos/doc/manual/from_md/release-notes/rl-2211.section.xml
@@ -98,6 +98,17 @@
           <literal>hardware.saleae-logic.package</literal>.
         </para>
       </listitem>
+      <listitem>
+        <para>
+          Matrix Synapse now requires entries in the
+          <literal>state_group_edges</literal> table to be unique, in
+          order to prevent accidentally introducing duplicate
+          information (for example, because a database backup was
+          restored multiple times). If your Synapse database already has
+          duplicate rows in this table, this could fail with an error
+          and require manual remediation.
+        </para>
+      </listitem>
     </itemizedlist>
   </section>
 </section>
diff --git a/nixos/doc/manual/release-notes/rl-2211.section.md b/nixos/doc/manual/release-notes/rl-2211.section.md
index 97ecb725dfb5..acad456a4fd3 100644
--- a/nixos/doc/manual/release-notes/rl-2211.section.md
+++ b/nixos/doc/manual/release-notes/rl-2211.section.md
@@ -45,5 +45,6 @@ In addition to numerous new and upgraded packages, this release has the followin
 ## Other Notable Changes {#sec-release-22.11-notable-changes}
 
 * A new module was added for the Saleae Logic device family, providing the options `hardware.saleae-logic.enable` and `hardware.saleae-logic.package`.
+* Matrix Synapse now requires entries in the `state_group_edges` table to be unique, in order to prevent accidentally introducing duplicate information (for example, because a database backup was restored multiple times). If your Synapse database already has duplicate rows in this table, this could fail with an error and require manual remediation.
 
 <!-- To avoid merge conflicts, consider adding your item at an arbitrary place in the list instead. -->