Postboks is not a finished product. There will be bugs. There will be strange behavior that potentially can have some sort of negative consequences in your life (sudden battery drain, mobile data usage, emails not available offline when you need them, etc). By joining the beta, you're ok with this.
If an email disappears: relax. Postboks doesn't have permission to delete emails, so the email is not gone yet. But: if Postboks moved it to the trash folder for some reason, Gmail will delete it after 30 days, so don't "wait and see" if something important goes missing. Please check "All emails" and "Trash" at gmail.com, or use the search feature.
If you run into problems, please contact me at email@example.com and provide as much information as you can about what went wrong. For more info, see https://simen.codes/app/postboks-inbox-replacement
In the box below, please enter the email address you use to access Google Play. It will be used to grant you access to the app, and I will use it to contact you about important announcements about Postboks.