How to tell which version of unity and xcode was used

I have a version of an app I think I built with Unity 4.1 that I've been trying to use in Unity 4.5.5 with Xcode 6.1 with some Prime31 plugins. I get build errors which I cannot figure out so I wanted to use an old version of the project with an older version of unity and xcode that previously worked. Is there anyway to find out what version of unity and xcode was used in the build that worked.