In order for beta users to be able to test preview releases more purposefully, it would be great to know on what to have a look at. Release notes on what specifically changed compared to the last stable version could enable beta users to specifically have a look at these features and test them more thoroughly.
This could lead to better feedback rates for the development and everyone profits from a more stable app.
Either include the differences to the last stable version on the preview dialog
Or, add a direct link to such release notes to this page.