All smartphones and tablets launching with Android 9 Pie will have rollback protection, a functionality Google first introduced with Android 8.0 Oreo last year. As first spotted by XDA Developers, Google's wording of the feature's requirements differs based on whether manufacturers are looking to upgrade their devices running Oreo to Android 9 Pie or natively implement the latest iteration of the mobile operating system into their upcoming products. In practice, the change will force all handset makers to adopt Android Verified Boot 2.0 in their future OS implementations, with that particular framework being the technology behind the firmware's rollback protection protocols.
Much like its name implies, the functionality is meant to prevent users from downgrading their OS versions by stopping devices from booting if the new Verified Boot tool detects an earlier firmware build was flashed onto them. While many handsets that launched with Oreo lack the feature, Google itself adopted it with the Pixel 2 series, as did the OnePlus with the OnePlus 6. Some other manufacturers such as Samsung use first-party solutions like Knox to prevent OS downgrades. Immediately following its Monday announcement, Android 9 Pie started being rolled out to all Pixel-series devices and the Essential PH-1, with more smartphones being set to follow later this summer.
The gradual manner in which Google introduced rollback protection and made it mandatory for OEMs is reminiscent of the launch of Project Treble, originally an Android 8.0 Oreo feature that was only required to be supported by devices running Oreo out of the box, but not those being upgraded to Oreo from any version of Nougat. That particular functionality has also been designed as a comprehensive solution meant to make the company's ecosystem more secure as a whole, coming in the form of a reworked Android framework that should help manufacturers develop and test OS updates such as security patches in a timelier manner and make the Android platform less fragmented. Rollback protection is actually co-dependent on Project Treble and cannot work without it in practice, with Google spending the better part of the last twelve months encouraging OEMs to embrace both solutions as quickly as possible so as to make their devices easier to support.