I have an app with 2 targets, the main app and a Today extension - to share settings between these targets I\'ve switched on the App Groups Capabilities, added a group gro
Eventually found the answer in the comments section of the original linked website.
to target App-Group settings instead of the App Targets user defaults, all you need to do is add “ApplicationGroupContainerIdentifier” as a key to the Root.plist of your Settings Bundle and set its value as your App-Group identifier
So, after adding the following to my Settings.Bundle Root.plist, both my main App and Today Extension are accessing the same user defaults.