Is there any way to run incompatible apps from future versions of macOS?

Solution 1:

In a word, No

There are differences in macOS versions, and if an app says "macOS Catalina or later" it means that it requires something that is specific to, introduced in and not in earlier versions of macOS.

For example if you have an app that requires macOS High Sierra or greater it will also (likely) work on Mojave and Catalina too, but not on Sierra.

So, sorry, but that app was written to use a feature of Catalina that is just not there in previous versions of macOS.

You could contact the developer and ask if it is possible but I would bet no.

Solution 2:

You're in luck. The "Noto" app is open-source and available outside the Mac App Store in a version compatible with your Mojave system.

You can download the DMG here:

https://www.brunophilipe.com/software/noto/releases/noto-1.2.dmg

UPDATE: In the comments I learn that you're not looking for the app named "Noto", but rather an app named "Noto - Elegant Note" on the App Store, and "Noto.ink" elsewhere. That particular app is not made from the ground up for macOS - instead it is their iOS app that they have converted to macOS using Catalyst. Catalyst is only available on Catalina or later, so you have no way of running that app on Mojave unfortunately.

Solution 3:

You could use something like Parallels to run a Catalina or Big Sur virtual machine on your Mac, and run the app in the virtual machine.

Virtualize got an older “guest” OS on a newer “host” OS often works to reach very far into the past. Often, you can also virtualize a newer “guest” on an older “host” but that sometimes works for one or two versions instead of tens of jumps.

Solution 4:

An Operating System is (crudely) a set of features for developers to use in their applications. The apps use these features when they are executed.

New OS versions introduce new features that devs can take advantage of in new apps.

If the feature isn't in the OS, the app can't use it, and so can't run.