https://wccftech.com/windows-10-cumulative-update-build-19613-1005-kb4558320-is-out/

Microsoft released Windows 10 Insider Preview Build 19613 last week bringing some general fixes and improvements to the Insiders in the Fast ring. The company has today released a cumulative update for this Insider Preview Build.

Windows 10 Cumulative Update Build 19613.1005 (KB4558320) is out today for those in the Fast ring. However, Microsoft says there are "no major changes" arriving with today's cumulative update.