Apple released iOS 8 Beta 5 on Monday. The new developer seed includes a host of fixes across the board in iOS 8, including developer APIs and user features.
HealthKit - Apple has added a data type for HealthKit for spirometry, which is the measurement of lung capacity. That's not to say that Apple is going to include a spirometer in an iOS device—the inclusion of a data type simply means that HealthKit will know what to do with that data should be it be sent to an iOS device.
Metal and OpenCL - Apple is continuing to hone Metal, the company's technology for GPU-accelerated advanced 3D graphics rendering and data-parallel computation workloads. Beta 5 includes a workaround for developers encountering trouble with shadow samplers.
Notification Center - API-related issues with widgetPerformUpdateWithCompletionHandler.
HomeKit - Apple informed developers they have to reset their home configuration.
Various - There are various other bug fixes that indicate progress in CarPlay, Backup and Restore, AVCapture, Contacts, Document Providers, and more.
The new release is a developer seed only for registered developers, and is not available in Apple's public beta program.
iOS 8 is expected to be released this fall.