Microsoft removed three Windows 10 version 1903 upgrade blocks today after resolving the three critical issues impacting the Windows devices blocked from updating. Microsoft is still blocking some Windows devices with compatibility issues from installing the Windows 10 May 2019 Update. Microsoft also released a support document designed to help users to troubleshoot Windows 10 update problems when dealing with update installation issues. Users who experience issues while installing the latest updates can follow this guided walk-through for fixing the errors. There are five compatibility update blocks in place for Windows 10 versions of 1903: Unable to discover or connect to Bluetooth devices Display brightness may not respond to adjustments;.
Source: https://www.bleepingcomputer.com/news/microsoft/microsoft-removes-three-windows-10-1903-upgrade-blocks/