Ahead of the upcoming Windows 10 November 2019 Update release, Microsoft has shuffled its preview rings and will now no longer offer Skip Ahead.
Previously, Microsoft offered the Fast Ring (less stable), Slow Ring (more stable), the Skip Ahead ring, and the Release Preview ring.
Skip Ahead was restricted to a limited number of users who opted in to that part of the Windows 10 preview program. It was intended for enthusiasts who wanted very early Windows 10 builds from Microsoft’s dev branch.