It can be done, but your package lists will get cabbaged. I did it on a workstation once, and within a year, the machine was unmaintainable...Especially when upgrading to the new stable (e.g. lenny to squeeze). It had all sorts of extra hoops to jump through...
Having done it, I would concur with those that say back up and do a fresh install. --b On Fri, Feb 3, 2012 at 4:02 PM, Bob Proulx <[email protected]> wrote: > Julien Claassen wrote: >> I just wondered, if it would be possible to downgrade my Debian >> distro from - say - Wheezy to Squeeze? I thought, that it must work, >> but I can't for the life of me think, which exact command to use. > > No. That operation is not supported. It would be almost impossible > to test all of the cases. And the need for doing so is much rarer. > Upgrading is a task that everyone needs, at least for security > upgrades. But downgrading is uncommon. > > An individual project package might downgrade just fine. But taking > the entire system back would be very unlikely to be completely > successful. > > The problem comes down to migration of configuration files and > migration of system configuration. When upgrading the postinst script > is coded to transition forward in time from older formats to newer > formats. And if there is a particularly troublesome problem at some > revision then specific cases can be coded around. The newer package > knows about the problems that were created in the older package. > > Downgrading is the opposite case. Now the older package would need to > know how to back out things that happen in the newer package. But at > the time that the older package was written the newer package had not > been created yet. Therefore in the general case it is impossible for > the older package to be able to handle all potential issues. > > For packages without any configuration files or anything except > executables in /usr/bin and documentation in /usr/share/doc the > downgrade will be trivial and will always work as expected. But for > other more complicated packages it might be required to purge, > re-install, then reconfigure. > > Over the entire system from something with as many changes as going > from Squeeze to Wheezy and then back this would be impossible. Take > for example the scripts that convert to the new tmpfs /run > configuration. All of that would need to be undone. That is too much > to ask. > > Bob -- To UNSUBSCRIBE, email to [email protected] with a subject of "unsubscribe". Trouble? Contact [email protected] Archive: http://lists.debian.org/cakmzw+z1njblahale0kfhfxmw69hqxoipznnweyhwmchdev...@mail.gmail.com
