My bot is receiving some undocumented fields

You can find all officially supported methods, objects and available fields in Telegram Bot API documentation.

In addition to those described in the documentation, Bot API servers may push non-documented fields due to various reasons, such as keeping backward compatibility or testing some features.

To be on the safe side, please only use the fields documented in the official site, since any non-documented field may be changed or removed at any time without further notification. We recommend you to make your bots ignore any extra fields of the update without crashing.