Highlighted features of OxygenOS Open Beta 21/12 are Parallel apps and updated launcher. Parallel apps let you run a parallel version of the same app using a separate account. For example, you can use two Facebook, Twitter, Whatsapp, and Instagram.

OnePlus Launcher is now updated to version V2.1.5 with double finger slide support, redesigned UI for folders, and optimized home screen folder icon. Below is the official changelog of OxygenOS Open Beta 21/12 for OnePlus 3/3T. OxygenOS Open Beta enables users’ early access to new features. However, note that the OTA update is available for those users who have signed up for the beta program. Other users can download and flash the ROM manually. – Launcher V2.1.5 (update): Brings double finger slide support, redesigned UI for folders, and optimized home screen folder icon. – Gallery V1.8 (update): Supports light theme and opening RAW format images – File Manager to V1.7.1 (update): Long pressing search items now shows edit operations – Call histories from the same person will now be merged (optimization) – Fixed increased battery consumption after connecting to a Bluetooth device (bug fix)

How to Download and Install OxygenOS Open Beta Manually

  1. Download OnePlus 3 Open Beta 21 full firmware package from here. For OnePlus 3T, download Open Beta 12 full firmware package from here.
  2. After downloading the firmware on your computer, follow this installation instruction. Note: If you prefer stable version, then stick on the OxygenOS 4.1.6 (current stable version) for OnePlus 3/3T which is also based on Android 7.1.1 Nougat. (Source – OnePlus)