
Oxygen OS Open Beta 4 has been released for the OnePlus 7 Pro and will hit the OnePlus 7 next week. There have been many system-level issues with both phones that are being addressed, such as screen flashing, mobile data disruptions after an upgrade and more. New features are also being added, such as raise to lower the ringtone and the transfer of iPhone data through iCloud with the OnePlus Switch app.
As this is a beta release, always backup your phone and expect potential glitches and stability woes. Beta releases are never final developments.

Here's the complete changelog for Oxygen OS Open Beta 4
System
– Fixed the screen flashing issue with setup while adding the fingerprint – Corrected accidental muting of a vehicle navigation system
– Issue of mobile data disabling after an upgrade has been fixed
– Visual effects of the permission pop-up window is optimized
– Optimized the black and white screen issues with some apps
– Improved system stability and fixed other known issues
Phone
– Added the “Raise to lower the ringtone” feature in Sounds & Vibration for incoming calls
– Enabled efficient addition of unknown numbers to contacts
– Optimized the description for the features
– Expanded the dial pad area to avoid mis-touches
Others
– Optimized the message sorting feature by verification code
– Optimized Calculator UI and interactive experience
– OnePlus Switch – Supported transfer of iPhone data through iCloud
– Weather Added The Weather Channel as a data source for accurate weather data
Oxygen OS open beta 4 is rolling out through an OTA for users already running an open beta on a OnePlus 7 or Pro.
source: Android Authority