there are 2 major camps when it comes to Firmware updates:
one wants all the latest functions automatically applied. for the most part, these users have gotten this from day 1 of updates for all these years.
the other camp wants to get the latest functions, but simply do not want their current sound/tones altered. until this revision, for the most part they always have had their tones changed (assuming the FW changes the tone). this has been a request from many users for a long, long time.
with this firmware, Cliff offered a way to introduce an update without automatically changing the tones. recently created Presets (since the Modeling Version option reappeared in Global and Amp blocks) will NOT have their tone changed because they will stick to the FW 3.xx option.
this is the first time that anything like this has been implemented. we can all update and our (recent) Presets will sound exactly like they used to, so you can go to your gig with 4.xx and sound like you expect without having to make changes before your gig.
a compromise had to be made to offer this, and that compromise was that, for now, if you want the Latest version of modeling, you have to manually change the Modeling Version in your Amp blocks to "Latest." (again, older presets do already automatically get updated to Latest).
the Firmware is 1 day old. maybe a way to update amps all at once is being developed. maybe not. we don't know.
all we know is that for the first time, this Firmware doesn't automatically change your tones, so after loading it, you at least sound exactly how you did minutes before loading. this is probably a great feature for majority of users.
perhaps we can ask nicely for a way to update our Amps and Presets all at once; maybe we'll get it.