Microsoft changes Windows 10’s update model

Fast Ring subscribers are the first to get new features and updates. Slow Ring subscribers get those features before they're public but not until after the Fast Ring folks have had a while to flush out the worst of the bugs.

If Microsoft continues in the vein that it has begun with 20H1 and 19H2, the Fast Ring will get longer periods of time to test the biggest and potentially more problematic major feature upgrades, and the Slow Ring will get the first crack at—and more time to test—the smaller incremental updates aimed at fixing long-term problems in performance and stability.