What's new in Android 9 (Pie)
Thomas Rutter

Android 9 (codenamed "Pie") continues the recent tradition of bringing battery life enhancements to Android, and also brings several enhancements aimed at learning how you use your phone to better predict what you would like to do next.

When comparing features between different versions of Android, it's important to acknowledge that a lot of the software that makes up a typical Android device is not a part of the core Android operating system but instead has been added by the device manufacturer.

As a result of this, it's not unusual for new features added to Android to have already been present in certain existing phones using older versions of Android, because they were custom modifications made by that phone manufacturer. The below list of new features are features that have made it into Android itself, and thus should now be available on all devices using this Android version.

What's new

Adaptive Battery

Android 9 brings a new addition to Android's battery saving features to supplement the existing Battery saver and Battery optimization ("doze mode") features, applying varying battery saving measures on a per-app basis even when Battery saver is turned off. The measures applied are based on your usage patterns of each particular app, which is where the "adaptive" comes in.


Under the hood this involves a new feature called App standby buckets. Android monitors how you use your apps, and automatically places apps into certain buckets depending on your usage of each app. An app that is currently being used goes into the Active bucket, but any other app not in use is allocated to one of the four following buckets, depending on usage patterns:

  • Working set
  • Frequent
  • Rare
  • Never

An app that you use every day, for example, will be in the Working set bucket, whereas one that you have not used for many months may be in the Rare bucket. The Never bucket is reserved for apps that are installed on your device but have never been opened.

Each bucket imposes more restrictions on battery and resource use by an app than the previous bucket, preventing it from doing too much processing in the background or using resources such as sensors or internet data.

Due to the restrictions imposed on background processing by apps in recent Android versions, apps that need to receive and respond to incoming messages must use Firebase Cloud Messaging (this is a replacement to Google Cloud Messaging), and their bucket will determine how often they are allowed to access awaiting messages, and thus how quickly they can appear to respond. The adaptive nature of the buckets means that, for example, a social media app that you use regularly will always receive incoming messages quickly.

Adaptive Brightness

Continuing the trend of "adaptive" features which learn from your actions, Android's new Adaptive Brightness is an enhancement to the Auto Brightness feature for controlling screen brightness. It attempts to learn how you like to change your device's brightness in different situations and begins to apply such changes automatically.

For users that set their brightness to "Auto" and never adjust it again, this feature will simply work just like "Auto" did. However, many users like to manually adjust their screen brightness according to different lighting conditions, preferring more control over letting the automatic brightness do it itself. The new Adaptive Brightness learns how these users adjust their brightness according to factors such as the time of day and the ambient light level and attempts to predict their preferred brightness based on past patterns.

Users who previously preferred manually setting brightness may as well try enabling this (it appears on the brightness control in place of the previous "Auto" setting). When enabled, it is still possible to adjust brightness like it is in manual mode, overriding the automatically chosen brightness.

Lockdown mode

Lockdown mode is a new security and privacy related mode which can allow you to secure your device's lock screen to make access harder by other people. It disables fingerprint or face recognition unlocking, ensuring that the device may only be unlocked by your pattern, PIN or password. It also disables all smart unlock features you may have enabled, such as automatically unlocking your device when it's at home, for example.

In addition, the content of messages is hidden on the lock screen, protecting privacy.

Lockdown mode may be useful if you need to provide your phone to someone you don't trust, such as security personnel, or to prevent somebody from forcing or tricking you into unlocking your phone using your finger or face against your will.

Lockdown mode is disabled on devices by default, and needs to be enabled in the Lock screen settings prior to using it. Once enabled, it appears as a new button on the Power button menu (the menu that appears when you hold the power button down for a few seconds).

Other new features

This release of Android contains many other features. Some of those not mentioned above include:

  • New support for devices with a "notch" into the middle of the top of the screen.
  • New support for gesture-based control of Android.
  • Enhanced ability to have a messaging conversation within a notification, without having to load your messaging app.
  • "Shush" mode, an enhancement to Do Not Disturb mode which activates upon placing the phone face down.