You can update your status, add comments, like or catch up the actions and do it from your iPhone in everywhere. So you will not miss anything from your community. In mobile version our new newsfeed is shown and you can switch to classic Grou.ps version (or mobile version too) bottom of page. For now it is not possible to join a group, you have to login your existing groups. 

We will  add new and special features for iPhone users in mid term.