When pigs fly,maybe.

It's a fact that updates release wise is never simple - even with Windows. You wouldn't expect to update Vista to Windows 7. No, you would just back up your stuff and do a clean install.

With Linux however, updating normally isn't that hard, you just save your user folder(s) (remembering the hidden folders!) and copy the content back after the upgrade. With SliTaz the install takes about 15 minutes (compared to 1 hour 30 minutes of Windows 7...) and configurations 'should' be transferable with your user folder. It will still require you to install the packages that you want and maybe some minor tweaking of the configuration to make things work like you'd expect.

I did an update from cooking to stable without having any problems - so it is possible. But backing up your files first is always necessary.
If you prefer a clean install you can backup a list of installed packages and reinstall them after upgrade. I'm not if this is the exact command, but it has to be something like that:

tazpkg list > installed_files.txt ### to get a list of all files in a textfile
tazpkg get-install-list installed_files.txt --forced ### to have tazpkg install the listed files

Good trick to know @Killerkaninchen - thanks :)