Indeed, they didn't officially confirm it.
first they change the OS name with the excuse of 3rd party software looking for 199x era strings
I'm pretty sure that was never confirmed by MS to be a reason, just something 'some dude' wrote somewhere which is now treated as truth..
I'm willing to be proven wrong of course, but naming tends to be more about long term promotional/prv/advertising than 'dumb code' if only because they could probably catch 99% of that software doing the dumb thing and spoof the return to be Win7 or whatever if needs be.
But some dude claiming to work at Microsoft said that that was the technical reason. And a simple examination of public known source code proved him correct, there is a horrible amount of software doing bad practices. Who knows about propietary software.
Probably this is the case of someone raising the very real concern from the technical side (putting a '9' will bring us trouble!) and the marketing guys got the perfect excuse to bump the number to 10.
And when marketing side hits and wins again technical side... A cuite kitten die D: