The App Store does not allow betas of any kind.
The App Store also does not allow developers to release products with versions of the development environment that support iOS 7, yet – until iOS 7 is released.
Users who are part of the Roomie beta program will of course get access to betas when they begin, but an actual iOS 7 release of Roomie is not allowed by the App Store to be available until iOS 7 is actually released. So any app you see with some comment like "Works with iOS 7" etc. is really just bogus, likely to break again the next day, and unable to support anything that's actually in iOS 7.
That leaves only the wild guess strategy if we wanted to fix something in some random iOS 7 beta, and meanwhile as is evident from this very thread users are saying it doesn't work in beta 1, then it works great in beta 2, then it doesn't work again in beta 3 because it's a moving target and thus impossible to track. With a typical 7+ day turnaround time to get a version on the App Store, any "fix" we'd make for whatever issue someone saw in an iOS 7 seed would be out of date by the time it was published.
Thus, iOS 7 support will be released when iOS 7 is released.
We do also plan to add a small number of (5-7) beta testers in specific areas to the beta program before we begin. We'll announce that when the time comes.
Thank you.