The name of the next Windows 10 feature update known as build 1903 or 19H1 may be called the April 2019 Update based on the output of the Get-VMHostSupportedVersion PowerShell command. The upcoming build 1903 update will include new features such as the Windows Sandbox and improved Windows Security features. As we get closer to the release, we will post an article describing all of the new features in this article. We will post a post-release article describing the features of the upcoming update.
Source: https://www.bleepingcomputer.com/news/microsoft/powershell-command-leaks-april-2019-update-as-next-windows-10-update/