He's done an 'in-situ' upgrade from 10 to 11, so installed applications should be unaffected. You should only have to reinstall your software if you've clean-installed Windows.

I think that's always been true, but there were technical and licencing reasons why you couldn't upgrade in-situ. ISTR For example that you could upgrade 7 to 10 in-situ (I did) but not if you'd upgraded to 7 from Vista. Or something like that.