So far, I’ve had a reliable experience in updating my 1st WIN10 v1909 laptop to v2004.   I am only updating one device now — for early pilot testing to look for early application issues.   Any “early adopter” ADMIN or “power user” should be technically versed to work around issues. 

When major releases appear, it is wise to cautiously wait a couple of weeks — as sometimes non-Microsoft software & drivers may not work as documented in early issues link below.  And in worst case scenario — there may be a need to revert back to v1909. 

Waiting allows installation experiences to improve where special software or hardware issues are discovered by early adopters & later resolved by OEM vendors.  Finally Microsoft’s automated update techniques are more highly advanced than in past — and tuned to distribute new feature releases lightly in the very early days of the release.  And the new version fans out more broadly later as early issues clear up.

Below are some excellent U-Tube video based resources on brand new v2004 “features” update for 1st half of 2020.  And some early issue links are also shared below

https://www.bleepingcomputer.com/news/microsoft/microsoft-is-investigating-ten-windows-10-2004-known-issues/