There're 2 kinds of group chat on Mixin Messenger, supergroup chat which supports unlimited participants and encrypted group chat which supports 256 members.
It exists as a bot, and it requires to deploy a server, and every bot has a bot ID, then it could be found by searching ID, for example, Mixin English group, the Mixin ID is 7000101502. For anyone who wants to create supergroup, please use our open source code: Mixin supergroup code
Small encrypted group
It could be created freely, and the chats are peer-to-peer encrypted, supports up to 256 participants per group. How to create it?
1. Press contacts icon at the top right corner
2. Press "New Group Chat"
3. Choose participants and press Next
4. Name the group and create
Only the group creator and admins have the right to check the group invitation link, it means that they could invite participants and decide who to join the group chat.