However, if you use an iOS device in public, a small glitch could expose your last visited website, even if you surf in Safari Private mode. As you know, when opening the App Switcher screen, to multitask between previously used software, all apps lingering in the background, display a snapshot of the most recent screen you were on before exiting. In iOS 8 and earlier, Safari would expose a screenshot of your last visited webpage even if Private mode was enabled!
Starting with iOS 9 this leakage gets corrected and Safari blanks out the App Switcher snapshot if the built-in Internet browser is currently running in Private mode. This way you’ll avoid unwanted sneak peeks when using your iPad, iPhone or iPod touch and are surrounded by others.
This is a similar Privacy addition to the one, introduced with the release of iOS 7, when Apple allowed iPhone users to hide incoming message previews from displaying on lock screen and other alerts like banners and Notification Center listings. This way you can avoid leaking important conversations to those unwanted eyes that could read your personal messages, when using the iPhone in the presence of others, or having it displayed on a desk or any other public location.