A SSU is available for Windows 10 version 2004 and 20H2. KB4586864 is the release that will improve the servicing stack for the Windows update installation.
Currently, there is no official information is made from Microsoft; we will update as it is available. Check –
Windows 10 Cumulative Updates List.
Servicing Stack Update KB4586864 for Windows 10 2004 and 20H2
Before installing KB4586781 any update you must have to install this SSU. There is no any prerequisite and you don’t have reboot the device after downloading.
How to Install
1. Via Automatic Windows update
2. Through Microsoft update catalog
Source – Mydigitallife forum.