The OnePlus 2 runs on an operating system that’s based on Marshmallow and the most recent software version is 3.5.5. The update is available over the air and it comes with VoLTE support, as well as many other things, but we’ll tell you more about them below.
According to the change-log, VoLTE functionality has been enabled for select carriers, the Volume Adjustment Bar has been redesigned, OxygenOS UI, Interface and UI of the Clock app have been updated, Android Security Patch has been updated to level 1/12/16, system stability has been increased, there have been made shelf optimizations, and the additions are: App Lock, Battery Saving Mode ( Settings > Battery > More ), Gaming Mode ( Settings > Developer Options) and more options for the Alert Slider. Also, many bugs have been fixed, so the flagship will run smoothly and crash more rarely.
The OnePlus 2 is now at the same level as this year’s flagships, but users who will encounter issues because of this update are able to downgrade back to version 3.1.0 by following these steps:
In settings > About, users will tap continuously on build number until users will get the notification that they are now a developer. After that, they will go back to Settings > Developer options, where scroll down until they will find the option to enable OEM unlocking. The phone will be rebooted into Fastboot Mode by pressing the Power and Volume buttons together for three seconds, then the device will be connected to a PC using a USB cable.
Users will open FLASH_TOOL.exe on their PC, then they’ll click “Choose Package” and select OnePlus2_310.zip. After that, they will head to “Other”, which is found at the top right hand corner and they will click on “UNLOCK OP2”.
Unlocking the phone will erase all data and users will confirm the action. The phone will reboot and users will tap on the FIRST option, then users will turn it off and enter again Fastboot Mode.
The phone will be again connected to PC and users will click “Flash” to start the downgrading process. It will take a few minutes until the phone will finally reboot to version 3.1.0.