The cumulative update preview for win7 went live a week ago, & that should show up automatically in Windows Update as optional.
All supported versions of Windows 10 *except this past May update [1903]* got the optional fixes a few days before that. Unlike win7, you have to check for updates manually for this cumulative update to show up.
neowin[.]net/news/microsoft-releases-windows-10-builds-17763592-17134858---heres-whats-new
Yesterday, the 27th, those win10 versions got another optional update.
neowin[.]net/news/microsoft-patches-older-versions-of-windows-10-with-a-single-fix
All of the updates come with the same fix for an issue that could prevent users from accessing Storage Area Network (SAN) devices using Internet Small Computer System Interface (iSCSI).
Also yesterday, 6/27, win10 1903 got it's 2nd cumulative update of the month. After checking for updates I received KB4502584 1st, which updates .NET 3.5 & 4.8. After restarting the option to download & install the cumulative update appeared.
neowin[.]net/news/microsoft-releases-windows-10-build-18362207---heres-whats-new
It fixes the most recent known issue with 1903 that effected Event Viewer, as noted on the page of 1903 known issues -- the remaining several problems remain unresolved.
microsoft[.]com/en-us/windows/release-information/status-windows-10-1903