Apple released the fourth version of the iOS 7 beta to developers today—a week late, given that Apple's developer center was down for most of the last week following a security issue.
The newest version of iOS 7 mostly contains improvements and bug fixes that center around the UIKit framework that governs how design functions the operating system, updates to iCloud integration, WebKit, media accessibility, how app connectivity displaces from Wi-Fi to cellular networks as well as a significant overhaul of Twitter application programming interface (API) behavior.
iOS 7 beta 4 was delayed by a week because of the security issues that have plagued Apple's developer center after a "security researcher" breached the store and showed Apple several of its vulnerabilities. Much of Apple's developer center is back online—just not all of it.
As an app developer, good luck if the iOS 7 beta breaks your app. The Apple Resource Center, Member Center, Developer Forums and Technical support are all still offline.
In addition to the iOS 7 beta 4 release, Apple updated iTunes to version 11.1 beta 1, Apple TV Software to beta 3 and Xcode Developer Preview to Preview 4.