I've searched several times and read conflicting posts on various parts of the internet telling me which Apple OS I can or can't use with my Adobe Photoshop CS6 Extended software.

Let's start with the assumption I don't want to pay an Adobe monthly fee because I only use Photoshop, and I believe I originally paid enough for how much I use it when I bought it. My copy of Photoshop currently runs perfectly well on High Sierra. Does anyone know which OS can I upgrade to and still be able to use it?

I would be really grateful for any information that anyone has. Thanks