1. Change `FUTURE_CODE_VERSION` flag to 0.
2. Open web client.
3. Add console.log() to log data received in `service-worker` and early return to skip this notification.
4. Send web notification.
5. Examine `service-worker` logs - ensure that encrypted payload is visible.
6. Using mariadb console ensure that version field of olm_session associated with cookie_id of current web client increments with each notication.