============
*Released 2021-06-06*
New Features:
- Arbitrary ``callback_data`` (:pr:`1844`)
- Add ``ContextTypes`` & ``BasePersistence.refresh_user/chat/bot_data`` (:pr:`2262`)
- Add ``Filters.attachment`` (:pr:`2528`)
- Add ``pattern`` Argument to ``ChosenInlineResultHandler`` (:pr:`2517`)
Major Changes:
- Add ``slots`` (:pr:`2345`)
Minor changes, CI improvements, Doc fixes and Type hinting:
- Doc Fixes (:pr:`2495`, :pr:`2510`)
- Add ``max_connections`` Parameter to ``Updater.start_webhook`` (:pr:`2547`)
- Fix for ``Promise.done_callback`` (:pr:`2544`)
- Improve Code Quality (:pr:`2536`, :pr:`2454`)
- Increase Test Coverage of ``CallbackQueryHandler`` (:pr:`2520`)
- Stabilize CI (:pr:`2522`, :pr:`2537`, :pr:`2541`)
- Fix ``send_phone_number_to_provider`` argument for ``Bot.send_invoice`` (:pr:`2527`)
- Handle Classes as Input for ``BasePersistence.replace/insert_bot`` (:pr:`2523`)
- Bump Tornado Version and Remove Workaround from :pr:`2067` (:pr:`2494`)