Just for my curiosity, and just at my private responsibilities and at my own risk, I "upgrade-installed" Windows 11 Pro 64 bit (Japanese) from Windows 10 Pro 64 bit running on my really old/outdated PC which is not used for daily operations.
The following description is not suggesting you trying the same, but just for your reference;
M/B: Asus P5Q Deluxe (no TPM)
CPU: Intel Core2Quad 9500 @ 2.83 Ghz
RAM: 16.0 GB
GPU: ATI FirePro V4800 (FireGL) 1GB GDDR5 on PCI Express 2.0x16 RAMDAC:400 MHz
SSD: Intel SSDSC2MH120A2 110 GB NTFS: MBR boot OS Windows 10 Pro 64 bit, in AHCI: SATA3
HDDs: two of 4 TB HDD, two of 2 TB HDD, all in NTFS in AHCI: SATA3
Monitors: two of EIZO FlexScan EV2750 via DVI, 2560x1440 each, 5120x1440 desktop
Running Windows 10 Pro 64 bit in Local Account and the highest Administrator mode (I always hate Microsoft official account)
1. Download the Microsoft official "Windows 11 install DVD iso image" (5.04 GB) (with selection of Japanese language in my case)
2. Load the iso image into Virtual Clone-CD/DVD Drive
( you can also "open" the iso DVD image by Windows Explorer)
3. Copy all of the contents of the install DVD into data HDD's "D:\temporary_Win_11_install" folder
4. Eject the iso image DVD from the Virtual Clone-CD/DVD Drive
5. Delete the file "appraiserres.dll" in the "D:\temporary_Win_11_install\sources" folder
(maybe, I did not need this deletion, though.)
6. Edit the registry as follows (maybe, I did not need all of them, though);
[HKEY_LOCAL_MACHINE\SYSTEM\Setup\MoSetup]
”AllowUpgradesWithUnsupportedTPMOrCPU"=dword:00000001
[HKEY_LOCAL_MACHINE\SYSTEM\Setup\LabConfig]
"BypassTPMCheck"=dword:00000001
"BypassSecureBootCheck"=dword:00000001
"BypassRAMCheck"=dword:00000001
"BypassCPUCheck"=dword:00000001
7. Open the "D:\temporary_Win_11_install" folder
8. Run/Execute the "setup.exe" with administrator rights
Edit: If you are asked whether to download updated installer files or not at the beginning of the installation, you should answer to it "no, not now!", otherwise the installer download the latest version with including "appraiserres.dll" which would reject your bypass preference.
Now, the "Windows 11 Pro" upgrade installation process started successfully.
At the end of the successful upgrade installation, my local account was also successfully inherited.
All of the hardware/software configurations remained just fine.
It looks all of the rather old devices and software (including all of the Microsoft Office 2010 software, JRiver MC 28, digital XO/DSP/EQ software EKIO, ASIO4ALL, etc., etc.) are just fine in operation.
Then I tried the "Windows Update" on the new Windows 11 Pro, and found at lease at present the latest cumulative update program for "Windows 11" (KB5005635) could be downloaded and successfully installed.