STS (Security Token Service) can generate credentials with much finer-grained control than just access to a whole bucket. You can require user authentication, do rate limiting, and set expire times. To allow a client to upload an image, for example, you can generate credentials that only grant privileges to a specific file location. It's much better than embedding master IAM credentials in a client.
They're signed with the same distribution keys and have the same app identifier prefix, so they have access to the same shared keychain storage on the device.
Apple only offers older versions of your app to users that have previously purchased it. New users will still get the traditional "this app requires iOS 7" failure message.
Awesome! I requested a DUNS number a couple weeks ago and planned on just waiting it out, but it looks like Apple already has my number after all. Thanks for the link.
http://www.tested.com/tech/robots/461486-maker-faire-2014-mu...