Two new tools were recently released onto the .NET scene to assist with identifying differences between assemblies. The two are actually complementary. The first is LibCheck from Microsoft, which displays API differences between two assemblies. The second is the Reflector Diff Addin, which actually displays differences in MSIL (in the language of your choice of course). The Reflector Diff Addin, of course, is an addin for Lutz Roeder’s fantastic Reflector .NET. Reflector just got better.