Interpretation 4.3a/1 addresses both paper and electronic versions. Essentially, the scale on your device cannot be enlarged beyond the limits set, and the device may not indicate a recommended line of play.
They are limiting green reading books to a certain "Scale" but I'm not sure how that applies to electronic green maps. My gut tells me an electronic app is not allowed under the rules of golf but I'm not an rules expert. Maybe legal as long as it does not violate the "Scale" requirements?