Update: The issue was resolved by Apple on Thursday afternoon, and non-developers can once again log in without issue.
Find My iPhone version 2.0.3 is now available on the App Store, with Apple saying it includes bug fixes and stability improvements. However, users without a developer account are advised to hold off on updating until any issues have been addressed.
"Developer Account Required," the error message displayed to users reads. "You must be a registered iOS developer and have iCloud configured on iOS 7.0 Beta to use this version of Find My iPhone."
The new Find My iPhone icon was already revealed last week, when the iCloud.com website was updated for beta testers to reflect design changes in iOS 7.
In addition, Apple also updated its Find My Friends application on Thursday to version 2.1.1, also advertised to include bug fixes and improvements. The application and its icon still feature the same stitched leather appearance, as it has not been updated to the cleaner style of iOS 7.