diff --git a/proposals/3866-user-not-approved-error.md b/proposals/3866-user-not-approved-error.md
index 7f8aa86f2..4cf31b873 100644
--- a/proposals/3866-user-not-approved-error.md
+++ b/proposals/3866-user-not-approved-error.md
@@ -87,5 +87,5 @@ them).
 
 ## Unstable prefix
 
-During development, `ORG_MATRIX_MSC3866_USER_AWAITING_APPROVAL` must be used
+During development, `ORG.MATRIX.MSC3866_USER_AWAITING_APPROVAL` must be used
 instead of `M_USER_AWAITING_APPROVAL`.