XP skins eventually stopped but if anyone still wanted one they are in library.  The same is true for 7 and 8 skins.  Plenty of them in the Library already.

I would drop 7 and 8 support even now.

plenty of windows 7 skins available. More and more people are adopting Windows 10, but there will always be those who keep a copy of 7 or 8 or even xp on their computer for whatever reason. but just concentrating on skins for Windows 10 would make your life easier in time saved etc.. but ultimately the decision is yours.

Microsoft Windows 10 43.7%  and Windows 7 35.61%  on top in terms of desktop/laptop users worldwide. MacOS X 10.14 comes third with only 4.91%

Check this:  https://techstartups.com/2019/10/25/microsoft-windows-10-now-used-popular-operating-system-world-2019/

bonjour tom

pour ma part je ne passerai pas pour le moment sur win10 ,je suis trè satisfait de win 7 , cela serai dommage de laisser tomber win7 , bon je me contenterais d'ancien skins de win7 , mais quand même, beaucoup resteront sur win7.

à vous de voir

Merci  

I use a Win 8 laptop and Win 10 skins work on it. Example Retiredmaster's skins work on 7,8 and 10 and he only uses one style. Is there a real difference between 7,8 and 10 skins?

For me Al, the biggest difference between 7, 8, and 10 is the Start Menu text colors, when it comes to skinning in SKS (Skinstudio), for example: if your left panel (Programs List) image is light colored, then you'd want to use a dark text, and if the right panel image (Places List) is dark colored, then you'd use a light colored text, this works fine on Win 8.1, and Win 10, but; it won't work on Win 7, you come up with an opposite results, so I create a sub style for Win 7, then do some tweaking in the settings to get it to match the text colors (for light/dark panels) in Win 8.1, and Win 10. I've wondered how those skinners only get by with one skin (sub style) for all three OSs, just with the example I laid out for you, it's been a mystery to me, I mean you can get it to work, if you never use two colored panels in the Start Menu, then you can get by using one colored text, which I do the majority of my skin. That's been my humble experience.   

Thanks Tom And Don. I did notice that loading some Win 7 skins had a messed up start menu on 10. 

Now I know why.

Any further comments from users?

I will make my decision the end of this month. As of right now, and sadly, I will probably be designing for Windows 10 only.