Two quick observations:
Today I was in an area with bad reception. At some point I got a notification about offline messages and I saw a notification with someone asking me something in a group. However, when I opened that group in Mitakuuluu, that message was not there. No idea what happened, but I did confirm that the person asked me something, so it was not an illusion.

Secondly, I just observed that when I click on a picture to download the full res image (am on WIFI right now) Mitakuuluu does download the picture, but for a moment the connection icon switches to mobile connection. No idea what's going on there.

Oh, and a general question, what exactly are the "offline messages" and what does the new "group offline messages" option do?

Thanks!