When One user A log In and then Log out. Then user B logs In. The notification intended for user A is received bu user B because the token generated for user A is not remov
You can accomplish that by calling deleteInstanceID. Be aware that deleteInstanceID automatically recreates the token, so you have to setAutoInitEnabled to false beforehand. You can check the current auto-init value by querying autoInitEnabled.
Note: requires firebase_messaging version 2.1.0 or greater.