Hey Steve,
is there gonna be a stable version, where updates dont wipe savegames?
No, but occasionally yes.
It's 90% likely the next patch will be 8.0.1 rather than 8.1.0, but it all depends on the seriousness of bugs we find and the extent of changes caused by suggestions implemented. And even then, at
some point there will be an 8.1.0.
Every release of Aurora will last as long as it lasts, and is subject to database-replacing upgrade at any time. If you're that concerned about replacing your game, don't start one for another month or so -- or at least until the patches are a week apart or more -- or live with an out-of-date game with fewer features and do your best to avoid any bugs that have been discovered in the mean time.