If you have installed the public beta of iOS 15, iPadOS 15, or macOS Monterey on any of your devices, you may have already tried out some of the new features Apple has added to the Notes app, such as the ability to use @ to mention users in shared notes and support for tags.
See also: iOS 15: Download and install the public beta on iPhone/iPad
See also: How to downgrade from iOS 15 to iOS 14
However, some iOS 15 users have discovered that Notes containing instances of these two new features are not appearing on some older versions of iOS and macOS, so it's best to stay away from these features if you have other devices that are still running older versions of Apple's desktop or mobile operating systems.
As reported by 9to5Mac, if the Notes app recognizes a device in your iCloud account that is running a version earlier than iOS 14.5 or macOS 11.3, it will alert you to the fact that notes with tags or notes containing mentions will be hidden on those devices.
See also: We choose if we want iOS 15! What does this mean for iOS 16?
On the other hand, if your other devices are fully up to date and running iOS 14.5 or macOS Big Sur 11.3 or later, it appears that any notes that use @ mentions or tags can be opened from those versions.
As always with beta software, it's not advisable to install this version on devices you rely on for work or anything else important, especially if you use multiple devices on the same Apple account.
Source of information: macrumors.com
