updated 10:51 am EDT, Wed July 16, 2014
Gap between betas shrinks back to two weeks
Apple is currently planning to seed iOS 8 beta 4 to developers on July 21, an inside source has claimed. That date would be two weeks after Beta 3. There was a three-week gap between the second and third betas, which may have been needed to cope with flaws hampering the OS' basic performance.
Work on iOS 8 should be finished by early to mid-September, in time for the launch of new iPhones. While mostly similar to iOS 7 on the surface, the upgrade adds a number of features, such as Extensions, Continuity support, iCloud Drive, QuickType, and Family Sharing. For developers, it adds dozens of under-the-hood tweaks and additions, like the HomeKit and HealthKit frameworks, along with significant App Store improvements.