How to revert from backports installation?

There would be no easy way as far as I know because your packages would be a higher version than are listed in the standard repos. You would have to uninstall the packages or use the --force option to "downgrade" them to lower versions. In theory this shouldn't inject any critical dependency issues, but if system dependencies are messed up you could run into some problems. Non system dependencies can usually be ironed out with a little effort, but if you run into problems in your system deps you'll probably have to reinstall.

With that said the backposrts repos shouldn't cause you any issues. Alternatively you could just compile the applications you want to update and install them manually...

Thank you for your answer.

I was thinking a bit more about the issue and I've come with an idea. Do you think this could work (deep dependency-messing apart, I mean)?

1. In some way, get from apt and/or dpkg the list of packages that are installed on the system and come from the backports repository. (Is there any way to do this?)
2. Remove the backports repository from /etc/apt/sources and update the package list
3. Force an apt-get reinstall for those packages in the list we got at point 1. (Or alternatively, remove them and then reinstall them).

Thanks.

That might work, though I don't think there is any automated system for downloading older versions of pacakges. You can always Force Version on packages from within Synaptic. However, if you have a system that works, there really isn't much point to trying to revert unless you are having problems with specific packages.