Bob Moore sent in a link to a story (Brooke Crothers, "Windows 10 will only work on newest PCs, says Microsoft", Fox News 1/18/2016), and commented:
I was confused when I saw this, because I am already running Windows 10 on several older PCs. When I read the article, I realized that what they meant to say was "Only Windows 10 will work on newest PCs, says Microsoft".
As far as I can tell, the editor who wrote the headline must also have been confused, since as far as I can tell, "Windows 10 will only work on newest PCs" can't possibly mean "Only Windows 10 will work on newest PCs".
This opinion is not a prescriptivist judgment about how the language ought to be interpreted, like most complaints about the placement of only, but a simple statement of how the phrase works (or doesn't work) for me. (And I suppose for Bob as well.)