Keep a copy of build 1803's ISO. You might NOT be able to grab it again.

Yeah I do a daily image backup anyways. However, it looks like my system
may not be compatible with this build, as soon as I began installing it,
within an hour, it stopped the installation and gave me an option to
revert back to the previous setup.

Same here. Lenovo E531 still on Win10 1803 because 1809 wouldn't or
couldn't finish the installation.