iCloud tabs is not working across all of my devices. I have two iPads running iOS 12, an iPhone X running iOS 13, and a Mac mini running macOS 10.15 Catalina. iCloud tabs only work between the two iPads and between the Mac and iPhone. The two iPads are older models that will not run iOS 13. Is there an issue with iCloud Tabs syncing between iOS 12 and the latest macOS and iOS versions? I've tried unchecking and rechecking Safari in iCloud settings on all devices and rebooting devices and nothing works.