While still labeled "experimental," IL2CPP (Intermediate Language To C++) was introduced to convert .NET IL code to C++ for better performance. 5.0.0f4 made the deployment of IL2CPP builds to iOS 64-bit significantly more stable, fixing a preceding crash related to exception handling.
// change these as needed private const string buildPathRoot = "Builds"; unity 5.0.0f4
public class MakeBuilds