Error - you need at least Windows 10 (version 1909)

[d2e3x4-1441]

[Main Thread] Error: You need at least Windows 10 (version 1909)

Howdy! I want to clarify that the bug here impacted players with supported Windows versions, and the fix was to reinstall the Battle.net Desktop app. In your case, if your version of windows is older than 1909. Then the error is correct, and you need to upgrade windows by running windows updates. If you are running into issues updating Windows then Microsoft support or a local PC repair shop might be best to assist you. Thank you.

This problem surfaced again today during login / maintenance by Blizzard today, while I was like worldwide d4 gamers, passively awaiting Queuing/Login Wait.

Why?
And What an Where is the solution, Blizzard?