TodayMicrosoftThe cumulative update for Release Preview channel release is KB4522355, and the RP users at the current 19H1 and 19H2 branches receive the update. In addition, the cumulative update comes with a new service stack update KB4525419.
The update log for KB45222355 is not on-line, but the 19H1 user is up to Build 18362.446 after installation, and the version number after the 19H2 user is upgraded to Build 18363.446. If unexpected, the cumulative update will log in to the production device for Windows 10 May 2019 Update (v1903) by the end of this month.
Windows 10 version 1909 itself lands as a cumulative update, so it also includes all previously released fixes. According to the latest leaked information, this windows 10 feature update is expected to be launched on November 12 for the first batch of devices. November 12 is also the next patch Tuesday cycle, and Microsoft will release new cumulative updates for all windows 10 versions.