Telegram Supergroups can have up to 5000 members each. They have a unified history, so deleted messages will disappear for everyone, and ordinary members can only delete their own messages.
1. The entire message history of the supergroup (that is, messages sent after the group was upgraded to supergroup) is visible to new members that join the chat.
2. Supergroups are muted by default if there are more than 200 members.
3. They can be made public by setting a username, see the demo group
4. In public supergroups, members can add new people. In private supergroups, new people can only join via invite link or if added by admins.
5. Members can edit their own messages within 48 hours of sending them.
6. Admins can pin messages, pinned messages are displayed at the top of the chat.
- You can only pin messages that were sent after the upgrade to supergroup, not before.
- A group member can hide a pinned message to stop seeing it. If this very message is pinned for the second time, members that have hidden it once won’t see it pinned again (even if this message has been edited).
7. In group members list, contacts are sorted from their last message. (First contact in the list is the person who sent the latest message, and last person in the list, the oldest one.) When you type @ in the text field, apps suggest people that have been active in the group lately. If there are up to 200 members, a supergroup behaves like an ordinary group.
8. Supergroups can have a short description, like channels.
9. When administrators or the creator remove somebody from the group, these users are blocked from the group. They can only return if they are invited by an admin, and they can't use links to enter to the group where they are blocked.
10. The number of administrators in a supergroup is limited (currently the maximum is 50).
11. Supergroups show less joined/left service notifications.
- Shortly after creation/upgrade, no notifications are sent.
- Left / removed notifications aren’t displayed if the group is too small, or too big, or if the last message in the group was sent many hours ago. Messages about bots being removed or added are always shown.
(Exact numbers may be changed a lot.)