Recently Apple shortened their review times from about 7 days to about 1 day.
You can follow the latest review times at appreviewtimes.com
How is Apple doing this? It could be new leadership. It could policy changes. It could be more people. While it may be all of these, I think it has something to do Automation.
Each year Apple has been getting better with their testing tools. In iOS 9, they made a big improvement with UI Testing tools. Xcode now allows you to record your UI Tests. Basically click a record button and then navigate your app in the Simulator. It’s a bit more complicated than that, but almost that easy.
What if Apple modified their testing tools, so the App Store Review team could record their review sessions. Once they have a recording for an app, they can run that recording on new submissions. If it passes, they approve the App. If it fails, they give the app a quick look through and fix the UI test.
They could have started recording session months in advance and then all of a sudden turned it on. If an App hadn’t been approved in a while or it was a new app, the first review would take longer. But after that, it would be fast.
I have no idea if this is what they are really doing, just fun speculation. I hope we’ll learn more at WWDC 2016.