There are hardware differences between the 3B and the 3B+, but you can get it to work. I put together a guide for the purpose: How-To Set Up and Upgrade Ubuntu MATE 16.04 on a Pi 2/3/3B+.
There are hardware differences between the 3B and the 3B+, but you can get it to work. I put together a guide for the purpose: How-To Set Up and Upgrade Ubuntu MATE 16.04 on a Pi 2/3/3B+.