If this is the same as all of Daz Studios other updates, have no fear about Daz Studio Pro 4 auto updating.  Every Daz Studio update to date has been a new installation, not a patch--so essentially you have to uninstall the old version and install the new one as a new installation--it should pick up on your content and preferences when you start a new version up--but as stated above other things may not work.  NO Betas for me, I'll ust sit back and use the version of Daz Studio 4 Pro I have.  This version of DS, for meanyhow, has been the most stable one I've had to date.

My solution to not having plug-ins work with later versions is not to buy any.  I do hope that Studio does stabilize in the future and that newer versions will have backward compatibility with older plug-ins and content.  One thing I've always admired about Poser is that it has excellent content backward compatibility--I just had a a few based items that were not upgraded and are now essentially unuseable.