For some, the most notable change is that one of the workarounds to skip the hardware check no longer works, and the easiest workaround today may not work tomorrow. The hardware requirements for Win11 are needed for Windows virtualization-based security features, which almost no home users [or gamers] want/need, because they make PCs & laptops slower and less powerful. Win11 runs more than fine on most hardware that does not meet Win11's requirements -- lower end hardware sees a performance boost compared to Win10 -- and while Microsoft tells everyone they should just buy a new PC/laptop, IMHO that's mainly to keep sellers happy... if you can't or won't buy a new PC, Microsoft would much rather you run Win11 than Win10, because Win11 gives them more opportunities to advertise and potentially make money off users. [Just the potential to make more money impresses investors, raising the stock price, which gives the execs a pay raise.] IMHO Microsoft isn't purposely trying to eliminate these workarounds, but they're glitches or bugs that may sometimes get repaired when Microsoft changes something else.
At any rate, today the easiest way to upgrade to Win11 24H2 on unsupported hardware is to download an ISO, mount it, right click the Start Button, click Run, then enter [Drive letter for the mounted ISO]:\setup /product server, then click OK. I've noted some other workarounds in the thread titled: Win11 24H2 Now Officially Available -- giveawayoftheday[.]com/forums/topic/473362
Another change that is a potential showstopper is a new Windows policy blocking a long list of drivers that Microsoft feels are too vulnerable to exploits &/or malware to let them run. Ideally you won't be effected, or if you are, you'll see a warning message when Windows starts that an old, forgotten driver you no longer need/use has been blocked, and all you have to do is check the box to never show you that message again and be done with it. Optionally of course you can go ahead and remove it, uninstalling or deleting the file(s) and any registry entries you come across using Regedit's search. Unfortunately if you need to use a blocked driver, which may be necessary for setup to complete & Windows to run, from a quick Google it looks like you'll have to wait a little bit until workarounds are discovered.
After Microsoft caused all sorts of headaches when an update earlier this year targeted the Recovery partition, it appears they've started rethinking their approach. In the last couple few years setup would create a Recovery partition, or reuse one that was already there -- it could also get confused and add a Recovery partition in addition to the one that already existed. I've seen 24H2's setup use the Recovery folder on a drive where the Recovery partition did not exist -- something it might also have done in the earlier days of Win10 -- and I've seen something new... on a drive with 2 copies of Win11 installed, one with a Recovery partition, one without, both copies now share the same Recovery partition (!). The Recovery partition holds a mini copy of Windows similar to WinPE intended to be used when you reset or reinstall Windows from the troubleshooting boot menu that can appear if Windows fails to start 3-4 times in a row. In the past the Recovery folder could also hold usually system-specific drivers. The location of the .wim file with this mini copy of Windows is registered in the boot loader [BCD] -- changing that location can stop it from working with that boot menu. If you don't want/need it, e.g., I do image backups, you can delete the Recovery partition and reclaim the disk space. Using Wiztree I was able to take ownership & then delete the .wim file in the Recovery folder to reclaim that space. diskanalyzer[.]com
Windows Update is still inconsistent [flaky]. During setup you have the choice to look for and install updates during setup or afterward -- by doing it later setup takes less time, and you reduce the chances of problems occurring. You should of course run Windows Update, looking for updates ASAP once the new version of Windows is installed. I've had the process fail if I did not first use Windows Tools -> Disk Cleanup to delete the old, unneeded files from the upgrade, which is a problem if/when you want to preserve the old copy of Windows that's now in the Windows.old folder to copy whatever files/folders or to preserve the ability to roll back the upgrade. I've also had Windows Update show different updates available in different copies of Windows after upgrading to 24H2 on the same PC (?).
And what I really hope was an isolated case happened to me upgrading this PC, with hardware that is supported in/by Win11. As I posted yesterday in another thread, when setup restarted the PC it would not boot -- after a BSOD I wound up with basically 3 choices in the boot menu: run setup & rollback the attempted upgrade; try to boot setup once again; run another copy of Windows. Turning off secure boot temporarily, and running setup from last month's Insider ISO worked -- the new official ISO did not, with secure boot on or off. This PC uses an older motherboard [x470] with Window's boot loader files on an NVMe drive -- it was difficult to get an existing copy of Windows running with the boot partition on the NVMe drive, and that may be the problem, or part of it. I also updated the BIOS firmware last month -- Gigabyte has gotten more BIOS firmware versions wrong that right, and that could be the problem, or part of it. Logically, the fact that 24H2 runs fine on this PC, and with Secure Boot enabled, means [to me anyway] that something in Win11's setup routine got screwed up. Likewise, the fact that the Insider ISO worked while the newer ISO did not, hints that whatever's screwed up is part of something Microsoft's intentionally changing.