OnePlus is one of several OEMs nowadays that offer a public beta programme. The OxygenOS Open Beta programme enables OnePlus smartphone users to get updates with latest features and security patches before the stable release is rolled out. The company's two smartphones from 2017 - OnePlus 5 and OnePlus 5T - are now getting a new OxygenOS Open Beta 13 an Open Beta 11 respectively. Notably, the key highlight of the latest update is Project Treble support. Additionally, the new versions bring some other features and optimisations including new accent colours and a refreshed user interface.
The support for Project Treble on the OnePlus 5 and 5T suggests that both the handsets will receive faster Android updates over their predecessors. Google had announced Project Treble ahead of releasing Android 8.0 Oreo last year to enable a vendor interface to speed up the software update process for manufacturers. The last Pixel models, including the Pixel 2 and Pixel 2 XL, already included the new development, but it did not come on the OnePlus handsets that had also received Android Oreo updates back then.
Project Treble is essentially designed to allow OEMs to easily update their device firmwares to the latest Android version, without being required to implementing any major changes. Google had separated the vendor implementation, including the device-specific, lower-level software written largely by chip makers, from the core Android OS framework. This makes it easier for OEMs to push Android updates shortly after Google releases new software versions from its end. In August last year, Google engineers on an Android Developers Backstage podcast episode confirmed that they are working with OEMs to bring Project Treble to a mass level. Interestingly, OnePlus has refused to provide Project Treble support on its older smartphones.
In the list of other new additions that come with the latest OxygenOS build, you'll notice a lot of UI-based improvements and tweaks, such as a new design for OnePlus' weather app and a new UI for the system app. The company has also introduced some changes to the default Launcher app, which now comes with improved search tags in the app drawer, 'New Installs' category tag in the app drawer and improved app list for hidden space and toolbox. Also, OnePlus has optimised logic for the contact page in the OnePlus Dialer app. OnePlus has posted the full changelog on its forums.
Since the latest OxygenOS build comes with Project Treble support, if you are not running Open Beta 12 for OnePlus 5 and Open Beta 10 for OnePlus 5T, ensure that you flash the builds before updating. Otherwise, you should clear all data and cache from recovery before flashing the latest build. Note that flashing will wipe the contents of the phone, and users will need to back up their data first. Of course, since this is beta software, there will be a fair share of bugs - thus, it is not recommended to run these versions on your daily driver smartphone.