1 files changed, 8 insertions, 0 deletions
diff --git a/docs/upgrade.md b/docs/upgrade.md
index 0d0bb066ee..95005962dc 100644
--- a/docs/upgrade.md
+++ b/docs/upgrade.md
@@ -106,6 +106,14 @@ You will need to ensure `synctl` is on your `PATH`.
     automatically, though you might need to activate a virtual environment
     depending on how you installed Synapse.
 
+
+## Compatibility dropped for Mjolnir 1.3.1 and earlier
+
+Synapse v1.55.0 drops support for Mjolnir 1.3.1 and earlier.
+If you use the Mjolnir module to moderate your homeserver,
+please upgrade Mjolnir to version 1.3.2 or later before upgrading Synapse.
+
+
 # Upgrading to v1.54.0
 
 ## Legacy structured logging configuration removal