Apple today released updates to the Find My iPhone and Find My Friends apps. While Find My iPhone 2.0.3 features a slightly new (and iOS 7-like) design, there's also one small issue -- users are reporting that the update doesn't provide the desired functionality (locating lost Apple devices) unless you just happen to be a developer. So for the time being, if you're not a developer, don't install the update.
Find My Friends 2.1.1 also includes the ever-popular "Bug fixes and stability improvements," but doesn't appear to have gained any flat design elements.
Update: Well, that was certainly quick. As of 3:30 PM ET, various source report that Find My iPhone is no longer displaying the previous error message, which was ""Developer Account Required. You must be a registered iOS developer and have iCloud configured on iOS 7.0 Beta to use this version of Find My iPhone."