Sending device to device notifications without server side code Firestore Cloud Messaging

Is it possible to send device to device notifications with 2 tokens of two different devices? I got confused in numerous articles. I have found this article https://medium.com/@mendhie/send-device-to-device-push-notifications-without-server-side-code-238611c143 , but it is deprecated and we can send notifications only by topic, not by users token.