Windows 10 version 1903 (also known as Windows 10 May 2019 Update) is now available to all users who manually check for updates using the Windows update dialog. Windows 10, version 1903 is available for any user who manually selects Check for updates s via Windows Update. Microsoft provides a dedicated support document to help customers troubleshoot problems while updating Windows 10. There are still six compatibility update blocks preventing Windows computers from receiving the Windows version 1903: Unable to discover or connect to Bluetooth devices with Bluetooth devices or audio not working with Dolby Atmos headphones.
Source: https://www.bleepingcomputer.com/news/microsoft/windows-10-1903-now-available-to-everyone-via-manual-update/