yeah .. and that new version would then get an other named saved variables addon ?
A user has to know which addons use which folders to know when he can remove them.
Always when I think about it, it gets even worse :9
Think we might be talking cross-ideas. Was talking about my alternative to Mikk's suggestion, there would be no new addon folder.
Say you have an embedded lib LibBooFar-1.0 it needs savedvariable BooFarVar which using something like the tiny bit of code above keeps in sync with multiple containing addons even if they load on demand etc. (Assuming data is stored with transactions / date stamps etc if necessary.)
A way to improve/rearchitect LibBooFar is found but needs a new data layout. LibBooFar-2.0 is created and request savedvariable BooFar2Var. BooFarVar is removed from the saved variable list. When LibBooFar-2.0 is loaded it watches for the variable BooFarVar which still should be loaded even if no longer saved (at least if I recall), merges into the new format as necessary.
still.. there is no big advantage to give an embedded library an extra addon to store data over not embedding the library at all.
the disadvantages like confusing the user that don't know what he can delete when uninstalling addons (and confusing updaters) are bigger in my eyes.