Microsoft doesn’t use RC [Release Candidate] or RTM [Release To Manufacturing] anymore, but both are still relevant & useful. The latest Insider build looks like it should be a Release Candidate – if no show-stopper bugs are found, it will be the next major release, 1903, due this month, & set for general release in April. There will be hot fixes for more minor bugs between now & general release, & often a cumulative hot fix is released along with the new version when it’s pushed out to everyone.
What happens next could be the release of an ISO, &/or the build’s release to the Insider Preview ring, though Microsoft has skipped both steps in the past. Then once this [or another] build hits RTM status, after it’s been used by more people for longer testing, there are typically leaks to journalists confirming that it's indeed the RTM.
While some people are just interested in getting the latest version soonest, to me these builds are useful for spotting problems before Microsoft pushes out a new version of win10 – when that happens, they don’t give me much choice, whether I want to upgrade or not, nor much time to find & test any fixes. Put another way, this puts me in control rather than Microsoft.
This PC has enough disk space to have a separate copy of win10 installed that’s enrolled in the Insider program’s slow ring. I’ll fire it up to upgrade & test compatibility etc. 1 – 3 times during the development cycle – using it I upgraded last night to the newest version [that hopefully will be the RTM]. And so far, so good – no real hardware compatibility problems that I can see. Next step will be a Windows To Go drive if Microsoft releases an ISO, which I can use to test everything else. If not, then after a disk/partition image backup, I’ll enroll the rest of our devices in the Insider program just long enough to get the RTM build.