Microsoft is now rolling out Windows 10 build 18356.21 as update KB4496796 for devices in the Slow ring of the Windows Insider Program. This is the preview build number 40 releasing to testers as part of the 19H1 development, and it’s available to resolve the issue which was prevent devices with build 18356.16 to upgrade to build 18362.
After installing the update KB4496796 on your computer running the build 18356.16, the version number will bump to build 18356.21, and in a few days, Windows 10 build 18362 should download and install automatically on your computer.
Download Windows 10 build 18356.21
Although there are no ISO files for Windows 10 build 18356.21, the update is available immediately through the Slow ring. This preview build will download and install automatically on your device, but you can always force the update from Settings > Update & security > Windows Update, and clicking the Check for updates button.
You can also check out these resources: