Hi, I'm Matt, an engineer on the Android team here at Strava. We love having users test out our new features before they're released to the full set of Strava users - it makes the product better for all. If you want to try out what we're working on before the public release, and don't mind the occasional bug or not-quite-there-yet feature, we'd love to have you on our Beta track.
We're running our Beta program through Google Play. Your regular Strava app will update more frequently, especially as we're approaching a public release.