Deluge of updates are coming from Apple. From iOS 8 to iOS apps to OS X Mavericks 10.9.5. Yes, you read it right. Apple releases OS X Mavericks 10.9.5 build 13F34.
Apple seeds OS X Mavericks 10.9.5 build 13F24
Apple seeds OS X Mavericks 10.9.5 build 13F24.
It is likely that OS X 10.9.5 would be released sometimes in mid September, 2014.