This is according to a tweet by the Financial Times’ Tim Bradshaw who received an email from Apple with a statement that reads, “We discovered a bug that prevents us from making HealthKit apps available on iOS 8 today. We’re working quickly to have the bug fixed in a software update and have HealthKit apps available by the end of the month.”
This is pretty disappointing news, especially in the face of other delays of iOS 8 features, like SMS Continuity and iCloud Photo Library that is only expected to be released in the next iOS 8 update which has been pegged for October and possibly alongside OS X Yosemite. In any case we guess iOS 8 users who have been looking forward to the feature will just have to remain patient for now.