Does updating from 1803 to 1809 break or change certain settings?  

Does updating from 1803 to 1809 break or change previously set:
- cacls policies
- software restriction policies
- exploit mitigation policies
- group policies
- user profile policies
- other unmentioned settings and policies
- does it re-install store and other system components that could or were disabled or removed by user
?

Also, if so - what is best way to do complete backup of previous version so in case of some major mess it would be possible to swiftly restore older version with exact same settings?

cereberus said:

1) It only changed a couple of things for me (reenabled hibernation,

I have to assume that's entirely random or due to the phases of the moon. Hibernation remains disabled on my PC after the upgrade.

What accounts for these variations?

Check graphics drivers, Nvidias were installed, same version as before the upgrade but not properly, missing OpenCL so need installing properly.

Thanks for answers. I'm mainly interested in "cacls", "SRP's" and "GPO's". Also missed question about Windows Services, I have some disabled or their default behavior changed.

worst case scenario: upgrading to 1809 may cause loss of personal document files as some users have experienced; see this recent ZDNet article:

https://www.zdnet.com/article/windows-10-october-update-problems-wiped-docs-plus-intel-driver-warning/

reminder to back up your files before upgrading to a newer Win10 release

also certain versions of the Intel Display Audio driver intcdaud.sys from v10.25.0.3 to v10.25.0.8 are incompatible with the 1809 release; obtain newest Intel HD Graphics drivers, which should include at least v10.25.0.10 of the Intel Display audio driver before moving up to the 1809 release.

Windows 10 build 1809 rollout was placed on hold.
The iso on the Microsoft website as of 10/6/2018 is build 1803

1809 changed my default audio settings. I had to restore "Speakers" as the default audio playback device and "Stereo Mix" as default recording device.