Ah, thanks, so it’s only the machine which I do the update on which is registered, and I won’t gain anything by using a different product key on the same machine? So once I’ve done the update I can then do a clean install of W10 on that machine at any point in the future and it will activate OK.
I’d wonder whether that trick would only work for the next year, but then presumably that would prevent people who had upgraded from re-installing if they needed to. I suspect I might just do a clean W10 install and Clonezilla it just to be on the safe side.
I’ve seen a few people have done this with VMs – presumably there’s some hardware identifier for the VM which gets stored with the activation servers? Has anybody tried then running multiple instances of the same VM (currently we do this with W7 using linked clones) – does it “phone home” and get upset when it finds multiple instances with the same ID? I suppose I might as well see if I can put my spare W7 product key to use that way.