Index: deploy/MULTI-INSTANCE.md
===================================================================
--- deploy/MULTI-INSTANCE.md	(revision 2dd1dc40db2f7dab2c095eeb309e5aaa02369b4b)
+++ deploy/MULTI-INSTANCE.md	(revision 5462bab0a30abfb9338812cb154a11cebda17b67)
@@ -133,4 +133,16 @@
 ```
 
+**Migrated before August 2026?** Then your `klonkt-update` still restarts the
+retired `klonkt.service`: the code updates but the running process never
+follows, and after the next update the site can 500 on pages whose template
+and route no longer match. Repair it once:
+
+```bash
+sudo systemctl restart klonkt@<slug>                        # load the current code now
+sudo bash /opt/klonkt/scripts/klonkt-refresh-updater.sh     # fix the updater for good
+```
+
+The migration script does this by itself nowadays.
+
 That pulls the code once into `/opt/klonkt`, reinstalls dependencies only when
 `package-lock.json` changed, and restarts every instance it finds under