Version 5.0.0 beta 4

applications/core/modules/admin/system/login.php

@@ -327,7 +327,7 @@ class login extends Controller
 	public function getCsrfKey() : void
 	{
 		/* Don't cache the CSRF key */
-		Output::i()->pageCaching = FALSE;
+		Output::setCacheTime( false );
 
 		Output::i()->json( [ 'key' => Session::i()->csrfKey ] );
 	}