I mean...yes. But also "Hello, is it me you're looking for?"
Loads of us run older machines that will still need access to 'features such as iMessage, FaceTime, and device activation' – especially if this basically means anything requiring iCloud or Apple ID login.
Basically this update is limited to 64-bit only OSes. Nothing with Rosetta 1 afaiu.
So, no Mojave, High Sierra etc. — which is a pain because I run High Sierra to access the late lamented, 32-bit only QuickTime 7 (there's nothing else like it) as well as a few other apps that were never updated to 64 bit. That machine certainly needs access to 'features such as iMessage and device activation' – and obviously to iCloud for all kinds of functionality and syncing.
You'd think the Pointdexters at Apple could find a way to continue certification for older OSes if they wanted to...
That aside (and it really does worry me, because it's not just a case of 'get a new Mac – you cheapskate' or update to Catalina if you can – it's a case of "Spend days changing your workflow and retraining your brain to work with apps that cost more than you can justify and which don't do what you need them to")...
Ahem, that aside, I hope this update fixes the well-documented and utterly ridiculous never-ending loop of "
Login to your ID account to update your settings" which Apple created in a previous Catalina update and seems to have otherwise ignored for years (for which none of the suggested workarounds works).
I live in hope.
Oh Tim Cook, who art in Infinite Loop, hear my prayer.