Installed stickersets have changed, the client should refetch them as described in the docs.
updateStickerSets#31c24808 flags:# masks:flags.0?true emojis:flags.1?true = Update;
|Flags, see TL conditional fields
|Whether mask stickersets have changed
|Whether the list of installed custom emoji stickersets has changed
Telegram allows including animated and static custom emojis inside of messages.
Telegram clients support displaying static and animated stickers.