This page lists changes in the Unity 2020.2 version which might affect existing projects when you upgrade from version 2020.1 to 2020.2.
To update Adaptive Performance from 1.0 to 2.0, see the Adaptive Performance upgrade guide.
The MacOS Standalone Xcode project building path selection has changed. Now you must provide the path to the desired directory, and the .xcodeproj and accompanying files are created inside the target directory. The MacOS build folder can not be inside the project directory. See the manual page for Xcode project structure.