@ilblog Hmm we have "Request Entity Too Large" error message trying to upload 1.6Mb pic. Running 1.11.1. Will ask or admins.
If you use Nginx check here for solution that worked for me.
that Admin can to send meseege to all users and mention a group of all useres
I don't think that there is one. But you could make one yourself, of course.
You could have the same effect, I think, by just posting in the group, though. Once you want to get a public message to everyone on the forum, the forum is the best mechanism for that.