How to Use the Ring/Silent Switch to Lock Screen Rotation on Your iPhone in iOS 9
The Ring/Silent switch on the side of an iPad or iPhone has always had one purpose—to toggle ring mode/silent mode. But in iOS 9, Apple is giving us another choice, and that's locking the orientation of the screen.
This could be a great new feature for some of you. Personally, I usually have my phone on silent mode, and I lock screen rotation a lot from the Control Center, so it's a welcomed addition on my iPhone.
Make your way into the Settings app, choose General, and scroll down until you find the "Use Side Switch To" section. There are two options: Lock Rotation and Mute (the default option).
Selecting the "Lock Rotation" option will allow the side switch to lock and unlock screen rotation simply by flicking it back and forth. Check out the new screen rotation heads-up displays (HUD) below.
 Unlocked,  Locked
As someone who's constantly sliding up the Control Center in order to manage orientation, being able to toggle the function using the side switch is a welcomed change. Plus, it gets rid of the rotation lock icon in the Control Center, which you no longer need. Unfortunately, this does not mean you get a mute icon in its place.
 When "Mute" is enabled.  When "Lock Rotation" is enabled.
Since this is an early beta build, this feature might not make it to the final release of iOS 9, but I'm hoping that it will and that they'll add additional functions for the side switch. In the meantime, stay updated with iOS 9 tips, tricks, and guides this entire week, as we'll be taking the brand new iOS apart to show you the best features it has to offer.