On iOS8, displaying my app in landscape mode will hide the status bar but on iOS 7 the status bar is displayed on both orientations

Try this

Add below code in didRotateFromInterfaceOrientation

[[UIApplication sharedApplication] setStatusBarHidden:NO withAnimation:UIStatusBarAnimationNone];

EDIT
NO NEED TO WRITE CODE IN ALL VIEW CONTROLLER
Set View controller-based status bar appearance to NO in plist and add below code in root view controller's viewDidLoad

[[UIApplication sharedApplication] setStatusBarHidden:YES withAnimation:UIStatusBarAnimationNone];[[UIApplication sharedApplication] setStatusBarHidden:NO withAnimation:UIStatusBarAnimationNone];

Demo project
https://www.dropbox.com/s/uumneidk4wom5md/demoStatusBar.zip?dl=0

To display status bar in landscape mode in ios 8, try following method

- (BOOL)prefersStatusBarHidden {    return NO;}

Swift version

override func prefersStatusBarHidden() -> Bool {    return false}

Swift 3, Xcode 8, iOS 10, /* ViewController.swift */

override var prefersStatusBarHidden: Bool {        return false    }

Jageen's solution is probably the best, with just one minor change i.e. instead of using viewDidLoad, it's better to use application:didFinishLaunchingWithOptions:.

It's basically a two step process:

1). Set "View controller-based status bar appearance" to NO, in your project's Info.plist file.

2). Force the status bar hidden status to NO, in application:didFinishLaunchingWithOptions:, using the following code:

[[UIApplication sharedApplication] setStatusBarHidden:YES withAnimation:UIStatusBarAnimationNone];[[UIApplication sharedApplication] setStatusBarHidden:NO withAnimation:UIStatusBarAnimationNone];

And, voila!

Note: It's important to use both the setStatusBarHidden:withAnimation statements above, to force the status bar hidden state.