More info here.
BarreNotes 2.4 update troubles?
Our recent app update shipped with a sneaky bug that will likely cause BarreNotes to crash when starting. The quick fix is to delete the app and reinstall from the AppStore. This will delete your favorites, solving the problem and letting the app work.
The real cure is hopefully to be found in update 2.5 which has been submitted to the AppStore and should be available for download within a day.