diff --git a/proposals/4350-appservice-encryption-impersonation.md b/proposals/4350-appservice-encryption-impersonation.md
index cf656545e..3e6ff6840 100644
--- a/proposals/4350-appservice-encryption-impersonation.md
+++ b/proposals/4350-appservice-encryption-impersonation.md
@@ -183,4 +183,6 @@ devices), so it should be easily noticeable.
 device metadata.
 
 ## Dependencies
-This MSC enhances [MSC4153], but does not formally depend on it.
+This MSC builds on [MSC4153]. While this proposal would technically work without
+4153, some security properties assume that 4153 is accepted either before or at
+the same time as this MSC.