Charles Proxy is a tool for OS X that can be used to facilitate the download of older versions of iOS apps from iTunes. It's a bit of a drawn-out exercise, but if you've ever been in need of an older version of a particular app, then you know how handy such a technique can be. In this video, which was inspired by this Reddit post, I'll show you how to download older iOS apps directly from iTunes on Mac.
How to download older versions of iOS apps