DOWNLOADMicrosoft released KB4522739, the cumulative update for the .NET Framework 3.5 and 4.8 for Windows 10 19H2 (version 1909) and Windows Server 2019 (1909), which improves the quality and reliability of the platform
Microsoft released the cumulative .NET Framework update KB4522739 for Windows 10 version 1909 (19H2) based on x64 processors (amd64), ARM64, and Windows Server 2019 (1909) for x64-based systems.
Installation through Windows Update
Cumulative Update 4522739 for PC installs through Windows Update. To check, go to the menu Options > Update and Security and press Check for Updates.
To complete the installation, you will need to restart your computer.
Install and configure Windows 10 updates
Improvements and fixes KB4522739
Details are available at support page.