@pepello@jae@GrapheneOS There are several channels: alpha, then beta, then stable. Releases are often announced when they get into the alpha channel, at which point is not visible by people being on beta or stable. After enough testing and if no issues are found, it gets promoted to beta (at which point it's not visible only to people on stable), and then on stable. It usually takes a few days to do this process from alpha to stable, but it depends on the changes introduced by the new version.
@pepello@jae You can see which release is in each channel for each device at grapheneos.org/releases#devices near the top of the same page. Releases go to Alpha, then Beta and finally Stable if they don't get cancelled due to regressions being spotted during public testing. We announce releases shortly before they go into Alpha so the release notes are already available before anyone gets the update. Our app updates also have Alpha, Beta and Stable channels in our App Store with a similar approach.