Originally Posted by Schturman

Man... Like I explained before, version 8.6 use DIFFERENT system UI app, you need to uninstall it from your system. it use "system-ui-extensions" and for uninstall it frm your system you need to ran this command as root from terminal:

Code:

apt-get remove --purge -y system-ui-extensions

or if you don't know to use terminal, just do it from tweak T, but IN VERSION 8.6 !
After this, reboot your phone and you can install 8.8 over 8.6 and you can use Tweak T (option 2) that will install "system-menu-extensions"
Good luck...