• Operating System version: Ubuntu 22.04 (Heroku)
• Firebase SDK version: 6.2.0
• Firebase Product: FCM
• Python version: 3.11.4
• Pip version: 23.2.1

I'm using FCM to send multicast messages from my Django app running on Heroku.

Since messaging.send_muticast() function is deprecated, I changed my code by using messaging.send_each_for_muticast(), as stated in the deprecation warning.

After pushing the new code to production, I often see multiple warnings in the Heroku application logs when the app sends messages: WARNING:urllib3.connectionpool:Connection pool is full, discarding connection: fcm.googleapis.com. Connection pool size: 10

Editing my code back to using messaging.send_muticast() seems to solve the issue.