https://core.telegram.org/bots/api-changelog#december-31-2019
- Added support for two new MessageEntity types, underline and strikethrough
- Added a new parse mode MarkdownV2
- Added the field file_unique_id to the objects Animation, Audio, Document, PassportFile, PhotoSize, Sticker, Video, VideoNote, Voice, File
- Added the fields small_file_unique_id and big_file_unique_id to the object ChatPhoto
- Added the field custom_title to the ChatMember object
- Added the new method setChatAdministratorCustomTitle to manage the custom titles of administrators promoted by the bot
- Added the field slow_mode_delay to the Chat object