There is a serious security issue in mobile app of rocketchat and it seams that rocketchat team doesn’t care very much. There is no progress on fixing this issue since July.
The description of the issue is here
So it is not secure to use rockectchat unless this issue is fixed
I suppose that here on forums mostly administrators of own rocketchat servers.
How are you using rocketchat with such issue. Aren’t you afraid that your users will unintentional leak their userid and authentication token?