diff --git a/proposals/3395-synthetic-appservice-events.md b/proposals/3395-synthetic-appservice-events.md
index 6b2dcf107..595e0022b 100644
--- a/proposals/3395-synthetic-appservice-events.md
+++ b/proposals/3395-synthetic-appservice-events.md
@@ -159,4 +159,4 @@ is not impacted.
 
 ## Unstable prefix
 
-All keys mentioned in this document beginning with `m.` will use `uk.half-shot.mscXXXX.` as the prefix.
+All keys mentioned in this document beginning with `m.` will use `uk.half-shot.msc3395.` as the prefix.