Or, I suppose, you could try using "System Events" to read the Bundle identifier key in the info.plist file inside the OmniFocus.app package.

(Looking first in /Applications/OmniFocus.app and then perhaps falling back to ~/Applications/OmniFocus.app if it wasn't found ...)

(But this kind of thing is, of course, hard to test because it is in the nature of the bifurcated bundle identifier problem that any given user only has one version installed, and can't test code for the other ... )

(I have asked the Ninjas whether there is a better solution to automatically detecting whether a user's data is in a com.omnigroup.OmniFocus cache or a com.omnigroup.OmniFocus.MacAppStore cache ...)

UPDATE see FAQ

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