Notable changes in version 81:

• add dedicated error message explaining how to work around an attestation failure occurring after a system_server crash by rebooting the device
• reword error message for an invalid number of Auditor app signing keys reported by the attestation data
• add more info to error messages for package info
• raise minimum supported Android version to 12 (API level 31) based on it being the oldest release with security support
• update CameraX library to 1.3.4
• update Guava library to 33.2.1
• update AndroidX AppCompat library to 1.7.0
• update Android Gradle plugin to 8.5.1
• update Android NDK to 26.3.11579264
• update Android build tools to 35.0.0
• update Gradle to 8.9

A full list of changes from the previous release (version 80) is available through the Git commit log between the releases.

The Auditor app uses hardware security features on supported devices to validate the integrity of the operating system from another Android device. It will verify that the device is running the stock operating system with the bootloader locked and that no tampering with the operating system has occurred. It will also detect downgrades to a previous version.

It cannot be bypassed by modifying or tampering with the operating system (OS) because it receives signed device information from the device’s Trusted Execution Environment (TEE) or Hardware Security Module (HSM) including the verified boot state, operating system variant and operating system version. The verification is much more meaningful after the initial pairing as the app primarily relies on Trust On First Use via pinning. It also verifies the identity of the device after the initial verification. Trust is chained through the verified OS to the app to bootstrap software checks with results displayed in a separate section.

This app is available through the Play Store with the app.attestation.auditor.play app id. Play Store releases go through review and it usually takes around 1 to 3 days before the Play Store pushes out the update to users. Play Store releases use Play Signing, so we use a separate app id from the releases we publish ourselves to avoid conflicts and to distinguish between them. Each release is initially pushed out through the Beta channel followed by the Stable channel.

Releases of the app signed by GrapheneOS with the app.attestation.auditor app id are published in the GrapheneOS App Store and on GitHub. These releases are also bundled as part of GrapheneOS. You can use the GrapheneOS App Store on Android 12 or later for automatic updates. Each release is initially pushed out through the Alpha channel, followed by the Beta channel and then finally the Stable channel.

GrapheneOS users must either obtain GrapheneOS app updates through our App Store or install it with adb install-multiple with both the APK and fs-verity metadata since fs-verity metadata is now required for out-of-band system app updates on GrapheneOS as part of extending verified boot to them.