I update my Windows manually. I give no credence to Microsoft. 
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To home! To forests and filelds! To lovely wife and son! To smiles and happynies!
I performed a search in my own regedit and couldn’t find any other places that you can change it.
I think only the CFP devs can answer what areas of the registry/filesystem are detected for OS.
Some program, who need to now OS version, check files version, such as ntoskrnl.exe or other.
And how to ask him (devs)?
??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ???
The only thing I can say now is try the 2.4 first in 32 bit. Let’s see if that works : link (english version) .
Xan