Big Sur & IOS16 compatibility

[JamesMay82]

I'm fully in the Apple eco system and use iCloud for iMessages, photos and iCloud Drive etc but I'm now on old hardware that is stuck on Big sur but I have a modern iPhone.

are there any compatibility issues with running a modern IOS that is syncing back to an older Mac OS? I'm mainly concerned about photos not being synced correctly and the same with important docs on iCloud Drive?

 

[saudor]

The problem is that they can drop support at any time. For instance, I had mojave and ios14 syncing great for the longest time. Then suddenly around May 2021, it became unstable/delayed. It will still sync but takes days for it to update. Moving to big sur and sync with ios14 was instant. Go back to mojave and the slow sync issue returned. Yet, any passwords saved before May 2021 would continue to sync immediately under Mojave.