FCM HTTP V1 API returns 404 for unregistered token

Question

FCM HTTP v1 API supposed to return error code \"UNREGISTERED\" when device is unregistered (app uninstalled). However API returns 404 \"Requested entity was not found\".

Answer 1

We face error 404 error code when sending notifications to Unregistered Devices via the old FCM endpoint:

https://fcm.googleapis.com/fcm/send

The documentation for API v1 has been updated and and does not contain this error code.