diff --git a/lib/types/keyserver-types.js b/lib/types/keyserver-types.js
--- a/lib/types/keyserver-types.js
+++ b/lib/types/keyserver-types.js
@@ -5,7 +5,7 @@
 import { tShape } from '../utils/validation-utils.js';
 
 // Once we start using the cookie field on web,
-// the cookie field type should be changed to string | null.
+// the cookie field should be mandatory, of type ?string.
 // See https://linear.app/comm/issue/ENG-4347/stop-using-browser-cookies
 export type KeyserverInfo = {
   +cookie?: ?string,