Features of Android Lollipop OS

Better WiFi and Bluetooth controls

Now you can choose your Wi-Fi connection directly from within the Notifications shade. 

You can now choose a wireless network or Bluetooth profile right from within the drop-down panel.

Better device protection

Phone theft is still a rampant issue, so Android Lollipop has a few new device protection features.

The most powerful of the bunch prevents a thief from factory-resetting the phone without the password for the Google profile used previously on the device.

Notifications can be flicked away

Individual notifications are now displayed on cards to adhere to the material design language, and batches of notifications can be grouped by the app that produced them.

Notifications are now displayed on the lock screen as cards. 

A do-not-disturb feature is also added for notifications.

Now a web browser can show all of its open tabs as individual cards.

Developing Features

Lollipop also contains major new platform features for developers, with over 5,000 new APIs added for use by applications.

For example, there is the possibility to save photos in a raw image format.

ART compiles apps upon installation.

ART is a cross-platform runtime which supports the x86, ARM, and MIPS architectures in both 32-bit and 64-bit environments. 

This technique removes the processing overhead associated with the JIT process, improving system performance.

No more crappy Wi-Fi connections

This is it’s favorite new feature of Android 5.1: if your device connects to a Wi-Fi network with poor or no Internet access, it'll remember that and never connect to it again.

This is great if you’re traveling or you’re trying to leech off of free Wi-Fi connections.

Better Battery Life

Lollipop also aims to improve battery consumption through a series of optimizations known as "Project Volta".

See the estimated time left before you need to charge, and when you're charging, see approximately how much time it will take to full charge.

Among its changes are a new battery saver mode, job scheduling APIs which can restrict certain tasks to only occur over Wi-Fi, and batching of tasks to reduce the overall amount of time that internal radios are active.

The new developer tool called "Battery Historian" can be used for tracking battery consumption by apps while in use.

Pick up where you left off

The songs, photos, apps, and even recent searches from one of your Android devices can be immediately enjoyed across all of your Android devices.

More tangible interaction

Content responds to your touch in an intuitive way.

Your device, your rules

For fewer worries and disruptions, adjust your settings so only certain people and notifications get through.

When it's important, respond directly from your lockscreen.

More ways to secure your device

Share your device securely with guest user mode.

Or create multiple user accounts to enable friends to log in on your device.

In either case, no one will be able to access any of your stuff.

And you can use Android Smart Lock to secure your phone or tablet by pairing it with a trusted device like your wearable or even your car.