Its been about 2 months since my last release, but trying to build one now I get.
path/MTOUCH: Error MT2002: Failed to resolve "System.Void Foundation.NSMutableDictionary::set_Item(ObjCRuntime.INativeObject,ObjCRuntime.INativeObject)" reference from "Xamarin.iOS, Version=0.0.0.0, Culture=neutral, PublicKeyToken=84e04ff9cfb79065" (MT2002) (OurApp.Touch)
Some searching around seems that this was removed a couple versions ago in the iOS platform, but I am not using it anywhere in my project, it is a standard forms project supporting android and ios.