T-Mobile is currently pushing an update to both the Samsung Galaxy Note 4 and Galaxy Note Edge which brings Advanced Messaging and Video calling to the smartphones. The update, which bumps both phones to Android 5.1.1 is available now as an over-the-air (OTA) download, or through Samsung's Kies software. No other changes or fixes are mentioned, but that doesn't mean there aren't some behind the scenes fixes included here as well.
If you've yet to receive the update, you can check manually by heading into your Settings, About Phone and checking there. Once you receive the update, be sure to let us know how it is working for you.
Newer model: Galaxy Note 5