The latest download links and downloads the previous beta.
Hey @Matust. Thanks for contacting us about the newest beta release.
We are aware that the version number in Settings > About shows 4.2.1b4, while the release notes show 4.2.2b1. These are actually the same version, but the version number in the app is wrong. We have an open issue, and this will be resolved soon.
In the meantime, rest assured that if you've installed 4.2.1b4, you're up-to-date. :)