Apple released iOS 11.3 in their public beta program 1/25. See below for additional info:
If you decide to update your device remember you can enter feedback via the "Feedback" app (App installs when iOS 11.3 installs).
Sign up here: Apple Beta Software Program
Once you register your device it will restart. After restarting go into Settings > General > Software Update
9 to 5 Mac link above has a great video of what is new in the initial beta for 11.3.
I've been with the Apple forum for years. Especially participating with the QuickTime media player. Apple would email me to take a test to run a new release which I would do. But I run several computers and would just take it on one. I would not advise anyone to do it especially if you have just 1 iPhone. I was rated high on the forum very into QuickTime so I could do it with them.