diff --git a/modern/src/runtime/Wac.ts b/modern/src/runtime/Wac.ts
index ad804d24..882ac95b 100644
--- a/modern/src/runtime/Wac.ts
+++ b/modern/src/runtime/Wac.ts
@@ -41,11 +41,9 @@ class Wac extends MakiObject {
     return unimplementedWarning("isvisible");
   }
 
-  // @ts-ignore This (deprecated) method's signature does not quite match the
-  // same method on MakiObject. This method is not used by any skins as far as
-  // we know, so we'll just ignore the issue for now.
-  onnotify(notifstr: string, a: string, b: number): void {
-    this.js_trigger("onNotify", notifstr, a, b);
+  onnotify(command: string, param: string, a: number, b: number): number {
+    this.js_trigger("onNotify", command, param, a, b);
+    return unimplementedWarning("onnotify");
   }
 
   onshow(): void {