Either earlier this year or late last year I read that this would likely be the new Windows 10 version upgrade method. The spring upgrade would be the one to add all the "nifty and often not wanted" new apps and features. The fall upgrade would not totally re-install Windows 10 as has been the case in the past but just fix issues and enhance some things from the spring upgrade. To get a good idea of what the upgrade to 1909 actually does read the following article. I found it informative.
https://www.thurrott.com/windows/windows-10/220060/windows-10-version-1909-reviewThis is partly speculation pieced together with things I've read and is not covered in the above article. Yes, the 1909 feature upgrade is more of an update than an upgrade but not for all systems. If you are running Windows 10 version 1903 or an earlier 1909 Insider's build this package will seem no different than a monthly cumulative update. However, if running a Windows 10 version earlier than 1903, it will be like a spring upgrade totally re-installing Windows 10 to bring it totally up to date.
As a note I have installed this update on both my desktops, laptop and virtual machine without issue. LOL! I think my laptop getting long in the tooth as the update went quicker on the virtual machine on my main system than on my laptop. Here is how it went with my different systems as to time. These are estimates as I didn't really time things.
Main system -- 3 minutes, probably less, closer to 2 minutes (no longer state of the art but still a beast).
Second system -- 10-12 minutes (it's an old dog
).
Laptop -- Probably 7-8 minutes (laptop is 8-9 years old running an early I5 CPU).
Virtual machine running on my main system -- ~5 minutes (It is using 4 of my 16 CPU cores).
