Portrait Rotation Screen Lock in iPhone 4S

How to lock your iPhone screen Portrait Orientation?

• Double press the HOME button and launch the App Switcher Bar.
• Swipe left in the App Switcher Bar to find the Portrait Rotation Screen Lock.

Portrait Orientation Lock

•  Tap the above button to lock the screen in Portrait Orientation and repeat the same to enable auto-rotation mode.

 Note: We use portrait as well as landscape orientation on an equal basis. We wish to have a Landscape Orientation Lock in the Apple's future release.