The official update for the 3B+ of ubuntu mate isn't out yet, there is a community written update floating about in this forum you could try. the boot problem sticky has some 3B+ related info on the "blue under voltage icon", it just means "you are using incompatible software". Thanks for your answ...

Hello there, I'm new to this forum, so I hope I'm doing this right... So I got a Raspberry Pi 3 Model B+ a few weeks ago and I have been using Raspbian as OS. However, I want to try Ubuntu MATE now because I think I might prefer it to Raspbian. I tried to install MATE 16.04.2 for Raspberry Pi on my ...