Bot API v.2.1. is here. We've added support for edited messages and new mentions from Telegram 3.9., and introduced a handful of new methods for group administrator bots.

Your bot can now get a list of administrators in a group, know how many members there are in a group and check a user's current status (administrator, creator, left the group, kicked from the group).

If a group starts getting on your bot's nerves, the bot can now leave it using the new leaveChat method.

Check out the full changelog here:
https://core.telegram.org/bots/api#recent-changes