One of my favorite cross-platform apps– macOS, iOS, iPadOS, watchOS– just received a major upgrade. Joseph Keller has the details and the how-to:
Apple made a lot of upgrades to Reminders in iOS 13 and macOS Catalina. With new features like Smart Lists, the quick toolbar, reminder subtasks, and Siri-powered reminder notifications in Messages, the default Reminders app is better than it’s ever been.
You just have to make sure that all your devices are running the latest and greatest versions.
It comes down to compatibility. Upgraded reminders for iOS 13 and macOS Catalina aren’t compatible with earlier versions of iOS or macOS, and thus, they will no longer sync.
Juli Clover has the complete list of details.