Happy to say that now my VPS is running openSUSE 12.3.The upgrade from 12.2 to 12.3 wasn’t a big deal. Here are the quick actions that initiate the upgrade :

1. Run a system update (zypper update)
2. Disable 12.2 repos
3. Add & refresh 12.3 repos
4. Full distribution upgrade (zypper dup)

For info, to quickly swap the repos, use yast. You can thus edit the existing URLs from 12.2 to 12.3. See below :

Doing the same from command line :

Refresh 12.2 repos

zypper ref

Apply the latest updates

zypper up

Replace 12.2 repos by 12.3

sed -i 's/12.2/12.3/g' /etc/zypp/repos.d/*

Refresh 12.3 repos

zypper ref

Do a full distribution upgrade

zypper dup