It’s the biggest update to iOS 11 yet.

Apple this week released its biggest update to iOS since releasing iOS 11 in September. iOS 11.3 introduces a slew of major new features for the operating system that runs on Apple’s iPhones and iPads.

Among the biggest feature is the new battery health monitor. Apple received a lot of criticism earlier this year when it was revealed that the company purposely slows down the performance of iOS so devices can last for longer on a single charge when the battery gets old.

While Apple’s move ensured that iOS devices last as long as always on a daily charge, no matter what the age of the battery, many felt Apple should have been more upfront making users aware of this fact. Now with iOS 11.3, they have.

But what else is in iOS 11.3? Here are all the biggest features.

iOS 11.3: New Animoji

This one only applies to iPhone X users because that device is the only one with the True Depth camera and Face ID. iOS 11.3 sees the addition of four new Animoji: a lion, bear, dragon, and skull.

iOS 11.3: Better AR

With iOS 11 Apple introduce ARKit, a dev tool that allowed developers to create mind-boggling cool AR apps and experiences on the iPhone. iOS 11.3 builds on ARKit with the release of ARKit 1.5.

This new kit now allows apps to use vertical surfaces like walls and doors to place AR objects on. Previously ARKit only supported horizontal services like tabletops.

iOS 11.3: Business Chat

Apple has added business chat features to Messages in iOS 11.3. This is similar to the way businesses can communicate with users on Facebook via Facebook messages.

Now when iOS users are viewing a business in Maps, Safari, Search or Siri, they'll have the option of tapping on a message button, which will allow them to text message the business directly. Right now this is a U.S.-only feature.

iOS 11.3: New Privacy And Data Transparency

Amidst the growing Facebook data scandal, Apple couldn’t have released this feature at a better time. Apple now explicitly tells users what data all Apple apps collect on their iOS devices and how Apple uses that data.

According to Apple, a new privacy icon and detailed privacy information will appear whenever Apple asks for access to personal information to enable features, secure Apple services or personalize an iOS experience.

iOS 11.3: Health Records

This is another U.S.-only feature for now. The new Health Records feature helps patients of more than 40 health systems in the U.S. view their medical records from multiple institutions right from their iPhone’s Health app including information about lab results, medications, conditions and more.

iOS 11.3: Battery Health

And finally, iOS 11.3 includes the aforementioned Battery Health status in the Settings app. Users can go to Settings > Battery to check the status of their battery health and see how its condition is affecting the speed of their iOS device.