What kind of feature are you missing? Where do you notice a shortcoming of PTB?

API 8.3

Describe the solution you'd like

• Added the parameter chat_id to the method sendGift, allowing bots to send gifts to channel chats.
• Added the field can_send_gift to the class ChatFullInfo.
• Added the class TransactionPartnerChat describing transactions with chats.
• Added the fields cover and start_timestamp to the class Video, containing a message-specific cover and a start timestamp for the video. (@aelkheir)
• Added the parameters cover and start_timestamp to the method sendVideo, allowing bots to specify a cover and a start timestamp for the videos they send. (@aelkheir)
• Added the fields cover and start_timestamp to the classes InputMediaVideo and InputPaidMediaVideo, allowing bots to edit video cover and start timestamp and specify them for videos in albums and paid media. (@aelkheir)
• Added the parameter video_start_timestamp to the methods forwardMessage and copyMessage, allowing bots to change the start timestamp for forwarded and copied videos. (@aelkheir)
• Allowed to add reactions to most types of service messages.

Describe alternatives you've considered

If you want to contribute, you can start from the Contribution Guide.

Additional context

Please comment below before start working on any part of the update so as to keep things in track and avoid double work.