Although Windows 10 version 1903, May 2019 Update, is already a complete product, it’s currently only available in the Release Preview ring for testers as a precaution to prevent possible issues as we’ve seen with previous releases. However, it appears that now version 1903 is unofficially available using an unreleased version of the Media Creation Tool without having to enroll a device in the Windows Insider Program.
The Media Creation Tool is a utility that allows you to perform an in-place upgrade or create a Windows 10 ISO to perform a clean installation of the latest update, which in this case is the May 2019 Update.
The link to download the MediaCrationTool1903.exe (read warning) was first spotted by HTNovo.net (via MSPowerUser.com), and it’s available through the Microsoft support website. However, it’s unlisted link, which means that the tool is not meant for public use.
Microsoft plans to officially launch the new feature update in late May, but if you can’t wait, you know the risks that involves installing a pre-release of Windows 10, and if the link hasn’t been blocked already, you can download the new Media Creation Tool to install the Windows 10 May 2019 Update.
Update April 14, 2019: The title has been updated, and a warning has been added to this article to clarify that the new version of the Media Creation Tool won’t install the May 2019 Update.
Update April 18, 2019: Although the Media Creation Tool won’t be officially available until late May, starting on April 18, you can download the ISO file to install Windows 10 version 1903 from the MSDN website (subscription required).