The one N5 feature I envied as a N4 owner is the screen off memo feature. Now a developer, xperiacle has ported over the feature for older Note users, [APP] Screen Off Memo [Update: 21 Sept 2015]. With version 1.3, he has made the Screen Off Memo feature work on the Note 4. It is an app that stock and unrooted N4 users can install. It works great. Also, xperiacle is responsive to posters on XDA, and I expect additional revisions as he further tweaks the app. I would highly recommend it.