Servers seem solid and there's also ejabberd but what about clients? I want clients that are stable, cross platform and does push notification and last time I c

Servers seem solid and there's also ejabberd but what about clients? I want clients that are stable, cross platform and does push notification and last time I checked, there were none. Also, I don't like the fact that it's person based whereas mattermost (and IRC) are group based that also allows person based chat.