If you go to the news section of minecraft.net on mobile, there are prereleases missing. I went to check them out on the feedback site, but the feedback site hasn't been updated to 1.21 or had newer snapshots after 1.20.6 prereleases. Please update the pages for newer snapshots, prereleases and updates. Also please change the 1.20 upcoming update to 1.21 in the feedback site.