Well now....I was having a really good look at on1 Photo Raw and lo and behold - I get an update advice from Adobe CC and have now successfully installed LR 8.0 and Photoshop 20 on my Windows 7 PC! There's still a blurb saying "Don't miss out on our latest and greatest release ever. Upgrade your OS", but it let me upgrade anyway. It will not let me install Lightroom CC - the non-Desktop-focused one - but that's OK, we're in Australia where it takes half an hour to upload a photo....if you're lucky...so have no interest in that anyway. ;-)

On the 'what's new' page for Photoshop, it says: "Beginning with the October 2018 release of Photoshop CC (version 20.0), the 32-bit version of Windows is no longer supported. For support with 32-bit drivers and plug-ins, use earlier versions of Photoshop." I had the free Nik software and none of it shows up in Photoshop (but DOES in Lightroom - Adobe really isn't known for consistency!!). The only thing that appears in Photoshop is On1 Develop and On1 Effects, which I have installed. I don't have any of the Topaz software.

Hope that sheds some light.