How to upgrade from xserver-xorg-lts-saucy to xserver-xorg-lts-trusty

You'll have to upgrade the named packages together:

sudo apt-get install xserver-xorg-lts-trusty \
    xserver-xorg-core-lts-trusty \
    xserver-xorg-video-all-lts-trusty \
    xorg-driver-video \
    xserver-xorg-input-all-lts-trusty \
    xorg-driver-input \
    xserver-xorg-input-evdev-lts-trusty 

If you get any errors about other packages with trusty in the name, add them to the list too.

Actually the correct way is to first fix the broken packages, so that you can remove it properly, before you install the new package.

sudo apt-get install -f

once it has installed all the missing dependencies, then run:

sudo apt-get dist-upgrade

when it finishes, at this point you have two choices, manually remove the package you are having trouble with, or doing the full release upgrade, which is the recommended method.

so you can either go:

sudo apt-get remove xserver-xorg-lts-saucy
sudo apt-get install xserver-xorg-lts-trusty

or you can do:

sudo do-release-upgrade

In the worst case scenario, if you already did upgrade to 14.04, but the xserver are still stuck on the old release for whatever reason, you can do this crazy move to remove all xserver files, so that you can re-install from the repositories.

sudo apt-get remove xserver*

doing that will also remove your Unity or Gnome, or whatever desktop environment you have installed, so you'll have to reinstall your choice of desktop environment, and that will automatically get you the missing xserver packages.

if you like the unity desktop do:

sudo apt-get install ubuntu-desktop

or if you prefer the gnome desktop do:

sudo apt-get install ubuntu-gnome-deskop