The following packages have been kept back:
  apparmor libgl1-mesa-dri libxfixes3 libxi6 lightdm lubuntu-default-settings
  xserver-xorg-core xserver-xorg-input-evdev xserver-xorg-input-mouse
  xserver-xorg-input-vmmouse xserver-xorg-input-wacom
  xserver-xorg-video-cirrus xserver-xorg-video-fbdev
  xserver-xorg-video-nouveau xserver-xorg-video-tdfx
  xserver-xorg-video-trident xserver-xorg-video-vesa
0 upgraded, 0 newly installed, 0 to remove and 17 not upgraded.