Hello,
The applications that now have been legacy products will be installed alongside the new. Legacy products will normally not be maintained. But you can use them as long as your system allow it.
You'll get the new applications.
The rest will be the same you have now.
if you allways wan't to be sure about the future using any plugin on the market, then you will be most secure, if you convert tracks to audio files and store those as stems.
But i never understand why so many updates products in the middle in products that seem very important.
However, it's allways possible to undo the Arturia install, if you suddenly can't load a plugin or the new has a bug.