Android 5.0 is known as Lollipop, available from November

What's New 
Lollipop introduces Google's sweeping visual refresh of Android, dubbed Material Design. Material Design introduces more white space to apps, brighter colours and shadows, giving the operating system a flatter, minimalist look. User interface elements are designed to scale based on the screen size they are on, helping maintain a consistent feel between Android Wear, smartphones, tablets and TVs. 

Notifications have received a major upgrade in Lollipop, and can now be interacted with directly from the lock screen. Lollipop also allows greater control over what apps trigger notifications and when.

Multitasking has also been updated, and each tab open in Chrome now appears as a separate entry in Lollipop's application swapper.

While it's been possible to create multiple user accounts on Android tablets since Jellybean, Lollipop brings the same functionality to smartphones. It's also possible to enable a guest mode, making it possible to share a device without sharing personal content.

Lollipop also improves handoffs between Wi-Fi and cellular networks. This makes it possible to, for example, continue a video call while switching from Wi-Fi to 4G.

Bluetooth device such as an Android Wear smartwatch will now able to unlock smartphones running Lollipop.