Windows 10 warns about updating to the May 2019 update

I guess depending on the version you use [I’m using Pro with a feature update delay] you may or may not see the message below when you should update to the Windows 10 May 2019 Update.

Obviously you probably shouldn’t install the May update through other means [MediaTool, ISO] if it’s giving you this warning.

BTW, I wish Microsoft would get their version format settled. Is it v1903 or 19H1? Is it v1909 [seen in the Windows Insiders] or 19H2?