Install MATE 1.12.1 In Ubuntu MATE 15.10 Or 16.04 Via PPA

The Ubuntu 15.10 and 16.04 MATE PPAs were updated recently with the latest MATE 1.12.1.

According to Martin Wimpress, Project Lead for Ubuntu MATE, the PPAs use the same source packages that he's done for Debian, which are currently being reviewed by the FTP masters and should land in Debian Unstable in a couple of weeks, so they should be safe to use.

Among the changes in MATE 1.12 (released about a month ago) are various fixes (for example: panel applets are no longer reordered when changing screen resolutions) and improvements for GTK3, including GTK 3.18 support, better touchpad and multi-monitor support and more. Check out THIS article for a complete MATE 1.12 changelog. I couldn't find a changelog for MATE 1.12.1.

In other Ubuntu MATE news:

• you you shouldn't need the Ubuntu Xenial PPA for long because as soon as the MATE 1.12 packages are accepted into Debian Unstable, they should be automatically imported into Ubuntu 16.04.
• the small MATE Dock applet I wrote about a while back was added to Debian Git recently by Martin Wimpress, and until Ubuntu and Debian reinstate the gir1.2-wnck-1.0 package (which was dropped a while back and is required by this applet), you can install this applet by using the Wily/Xenial Ubuntu MATE PPAs.

Upgrade to MATE 1.12.1 in Ubuntu MATE 15.10 or 16.04

To upgrade to the latest MATE 1.12.1 in Ubuntu 15.10 using the MATE Wily PPA, use the following commands:

sudo add-apt-repository ppa:ubuntu-mate-dev/wily-mate
sudo apt-get update
sudo apt-get upgrade

For Ubuntu 16.04 Xenial Xerus, use the following commands to upgrade to the latest MATE 1.12.1:

sudo add-apt-repository ppa:ubuntu-mate-dev/xenial-mate
sudo apt-get update
sudo apt-get upgrade

For both Wily and Xenial, to install the MATE Dock Applet I mentioned above, use the following command (after upgrading to MATE 1.12.1):

sudo apt-get install mate-dock-applet

How to revert the changes

If for whatever reason you want to downgrade MATE back to the version available in Ubuntu MATE by default, use the following commands:

- for Wily:

sudo apt-get install ppa-purge
sudo ppa-purge ppa:ubuntu-mate-dev/wily-mate

- for Xenial:

sudo apt-get install ppa-purge
sudo ppa-purge ppa:ubuntu-mate-dev/xenial-mate

The first command installs PPA purge and the second command purges the PPA (disables the PPA and downgrades all the packages installed from that PPA).