As the April 2019 Update is near finalized, Microsoft is now pushing Windows 10 build 18342.8 for devices enrolled in the Fast ring of the Windows Insider Program. This is the 26th preview releasing as part of the 19H1 development, and the first one available in the Slow ring.
Windows 10 build 18342.8 doesn’t include new features or significant changes other than the same improvements available in the same build released on February 20 in the Fast ring.
Some of these improvements, include the ability to access the Linux files using File Explorer, undisclosed changes for gaming, and general fixes.
You can check out this video review with build 18342.8.
Download Windows 10 build 18342.8
Although there are no ISO files for Windows 10 build 18342.8, 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: