I tried buiding my iOS game to support 64-bit as per new Apple requirement:
https://developer.apple.com/news/?id=01192015a
The new Unity 4.6.1p5 supports 64-bit build via the Player Settings->Configuration->Scripting Backend set to IL2CPP:
http://unity3d.com/unity/qa/patch-releases/4.6.1p5
During Unity's build process I got these errors:
------------------------------------------
2CPP error for method 'System.String com.shephertz.app42.paas.sdk.csharp.util.Util::MultiPartRequest(System.String,System.String,System.Collections.Generic.Dictionary`2<System.String,System.String>,System.Collections.Generic.Dictionary`2<System.String,System.String>,System.Collections.Generic.Dictionary`2<System.String,System.String>,System.String,System.String)' in assembly '/Users/Caster/Data1/TOTu/TOT3_64/Temp/StagingArea/Data/Managed/App42_Unity3D_SDK_2.9.4.dll'
Additional information: Build a development build for more information. An instruction cannot end both a catch and a finally block!