This page gives the directions how to upgrade your Debian distribution
How to upgrade your distribution
Upgrading from one stable release to the next (e.g. Wheezy to Jessie) is done by following the release notes for your architecture. For most people with 32 bit systems that means the Release Notes for Intel x86. For most with 64 bit systems that means the Release Notes for AMD64.
Minor upgrades are done with the package management tools:
Switching from GNOME to Xfce before upgrading
Optionally, you do not need to upgrade to the resource hungry GNOME 3 with wheezy, and can save bandwidth, by switching to Xfce before doing the actual upgrade:
Remove gnome and its dependencies:
aptitude purge `dpkg --get-selections | grep gnome | cut -f 1` aptitude -f install aptitude purge `dpkg --get-selections | grep deinstall | cut -f 1` aptitude -f install
Install Xfce:
apt-get install xfce4
For useful utilities that come with Xfce:
apt-get install xfce4-goodies
See also
?Lenny2SqueezeUpgrade