Microsoft is pushing a new update to devices with Windows 10 May 2019 Update (version 1903) and Windows 10 October 2018 Update. The August 2019 cumulative update for Windows 10 includes security enhancements for Microsoft Edge, Internet Explorer, Bluetooth and other core features. The update is rolling out via Windows Update, Microsoft Update Catalog and Windows Server Update Services (WSUS for business) Microsoft is also rolling out a compatibility update for devices with the October 2018 update (version 1809) This patch includes improvements to ease the installation experience when updating to Windows 10.
Source: https://www.bleepingcomputer.com/news/microsoft/windows-10-cumulative-update-kb4512508-and-kb4511553-released/