I had ArcMap 10 Add-In project built with ArcObjects SDK for .NET 10.1 where I could not reference external COM DLL build on .NET 4.0 due to a .NET forward compatibility issue. (ArcObjects SDK 10.1 uses .NET 3.5 SP1)
I wonder if the newer ArcObjects SDK 10.2 release targets the .NET 4.0 framework. That will solve my problem.
Does anyone know? Thanks