Jio and KaiOS have push notification systems
Research how the push notification API work on KaiOS.
Research if we can send client side notifications
Notifications can be a blanket message to all users e.g. asking them to update due to the resolution of a major bug; or a message to a select number of users for example for re-engagement.
For this spike, focus on experimentation with infrequently notifying users with custom notifications.