I think that this is probably a specification.
When the user specifies the channel name with 2-byte characters, it is noted with red letters “Name must be lowercase alphanumeric characters of two or more letters”.
Currently it is once created in alphabetic characters and modified to 2-byte characters after channel generation.
2-byte characters can be used with PC version, PC web browser, smartphone web browser without problem.
Will this be a feature request? Or is there a way to make it happen?
Mattermost 5.8.0, iOS apps 1.16.1, iOS 12.1.4