If the Patch Manager server has an Internet connection through your corporate firewall, the upgrade automatically installs Microsoft .NET FrameWork 4.8 during the upgrade, if required. If an Internet connection is not available, you must download .NET Framework 4.8 from the Microsoft website and install prior to the upgrade.
Back up your Patch Manager environment before you upgrade any .NET Framework, as removing older versions break the Patch Manager installation. The .NET Framework version 4.8 replaces any earlier version. After the upgrade, reboot your Patch Manager server.
If an error displays in the Patch Manager Administrator Console after you upgrade, see this KB article.