i have tested the proposed package and it works (on ubuntu-MATE 17.10 clean install)
on a clean install of ubuntu-MATE 17.10 (iso from october 2017) , then the usual standard sudo apt update, sudo apt upgrade... then checking the setting in "pre-released updates" in developers options in software & updates... then running sudo apt update, sudo apt upgrade to get the proposed updates, then running the sudo do-release-upgrade -d the upgrade to bionic beaver 18.04 works... the upgrade to bionic beaver 18.04 (ubuntu-MATE) will not work if you do not apply the updates in the to the bionic-proposed.. in short, if you are Upgrading ubuntu-MATE from 17.10 to 18.04 you need the bionic-proposed updates... otherwise the update will not work. IMO it is fixed with the bionic-proposed. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1750465 Title: upgrade attempting to process triggers out of order (package plymouth- theme-ubuntu-text 0.9.2-3ubuntu17 failed to install/upgrade: dependency problems - leaving triggers unprocessed) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/apt/+bug/1750465/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs