FAQ #16555, published on 2018-04-11
Should I worry about an email from Google starting with "In 2016, we launched Firebase Cloud Messaging (FCM), the successor to Google Cloud Messaging (GCM) ..."?
This email from Google is to announce you the upcoming abandonment (2019) of a technology (Google Cloud Messaging or GCM) that is no longer used in WINDEV MOBILE since version 22.

http://doc.windev.com/en-US/?1000022215

So don't worry if you are using WINDEV MOBILE 23 (or WINDEV MOBILE 22).

If you are using a previous version of WINDEV MOBILE, and if your application must use PUSH notifications in Android, then you must upgrade this application before April 11, 2019 and implement the Firebase Cloud Messaging syntax.