diff --git a/proposals/xxxx-stripped-state-events.md b/proposals/3173-expose-stripped-state-events.md
similarity index 99%
rename from proposals/xxxx-stripped-state-events.md
rename to proposals/3173-expose-stripped-state-events.md
index c2408f08..f2b04096 100644
--- a/proposals/xxxx-stripped-state-events.md
+++ b/proposals/3173-expose-stripped-state-events.md
@@ -1,4 +1,4 @@
-# MSCXXXX: Exposing stripped state events to any potential joiner
+# MSC3173: Expose stripped state events to any potential joiner
 
 It is currently possible to inspect the state of rooms in some circumstances: