Microsoft has released Windows 10 Insider Preview Build 18358 (19H1) to Insiders in the Fast ring. This release is mostly bug fixes as the build gets ready for release. It includes a fix for low streaming and recording quality in Game Mode. Microsoft is also introducing the Windows Defender Application Guard browser extension for Chrome and Firefox. This extension is designed to redirect untrusted sites to isolated Microsoft Edge sessions, where any actions in the browser do not affect the computer. Microsoft has added even more slots for Insiders to get the game State of Decay for free (for a limited time)
Source: https://www.bleepingcomputer.com/news/microsoft/windows-10-insider-preview-build-18358-fixes-poor-game-performance/