Thanks, max!
Following up on your comment, I tried "ppa:ubuntu-x-swat/x-updates", too (full command-line below) -- and for me that also did the trick. This PPA is a little less bleeding-edge than "xorg-edgers" (obviously), so some might prefer it.
sudo add-apt-repository ppa:ubuntu-x-swat/x-updates && sudo apt-get update && sudo apt-get upgrade
Thanks, max!
Following up on your comment, I tried "ppa:ubuntu- x-swat/ x-updates" , too (full command-line below) -- and for me that also did the trick. This PPA is a little less bleeding-edge than "xorg-edgers" (obviously), so some might prefer it.
sudo add-apt-repository ppa:ubuntu- x-swat/ x-updates && sudo apt-get update && sudo apt-get upgrade