[bonzini]

One issue we had with Mattermost is that some authentication modules (e.g. OAuth) are not part of the free core. Rocket Chat does not have this issue, though the mobile app is a bit less polished.

[engelgabriel]

Hi, we agree, and that's why we are about to launch brand new native apps for iOS and Android. Let me know if you'd like to join the beta testers.

[bonzini]

Yes, with pleasure!