1 files changed, 9 insertions, 0 deletions
diff --git a/develop/upgrade.html b/develop/upgrade.html
index f892a8b72e..0a33a344eb 100644
--- a/develop/upgrade.html
+++ b/develop/upgrade.html
@@ -260,6 +260,15 @@ dpkg -i matrix-synapse-py3_1.3.0+stretch1_amd64.deb
 </code></pre>
 </li>
 </ul>
+<h1 id="upgrading-to-v1570"><a class="header" href="#upgrading-to-v1570">Upgrading to v1.57.0</a></h1>
+<h2 id="changes-to-database-schema-for-application-services"><a class="header" href="#changes-to-database-schema-for-application-services">Changes to database schema for application services</a></h2>
+<p>Synapse v1.57.0 includes a <a href="https://github.com/matrix-org/synapse/pull/12209">change</a> to the
+way transaction IDs are managed for application services. If your deployment uses a dedicated
+worker for application service traffic, <strong>it must be stopped</strong> when the database is upgraded
+(which normally happens when the main process is upgraded), to ensure the change is made safely
+without any risk of reusing transaction IDs.</p>
+<p>Deployments which do not use separate worker processes can be upgraded as normal. Similarly,
+deployments where no applciation services are in use can be upgraded as normal.</p>
 <h1 id="upgrading-to-v1560"><a class="header" href="#upgrading-to-v1560">Upgrading to v1.56.0</a></h1>
 <h2 id="groupscommunities-feature-has-been-deprecated"><a class="header" href="#groupscommunities-feature-has-been-deprecated">Groups/communities feature has been deprecated</a></h2>
 <p>The non-standard groups/communities feature in Synapse has been deprecated and will