diff --git a/PLAN.md b/PLAN.md
index f8551f35bab68640baff03394607ebe124db06dd..e3357aa63eb1357cc486b57294ee316439f9fd99 100644
--- a/PLAN.md
+++ b/PLAN.md
@@ -331,7 +331,7 @@
 preceding gate passes. If a feasibility gate fails, change the design before
 you continue the feature work.
 
-**Current milestone:** Milestone 5.4 — Merge.
+**Current milestone:** Milestone 5.5 — Branch rules.
 Update this marker only after the current milestone gate passes.
 
 ### Architecture