Using Configuration Files with Shared Assemblies
You can still use the configuration files with shared assemblies. In fact, because the GAC can hold multiple versions of an assembly, configuration files become extremely useful for indicating the version that should be used with a particular client.
By default, a client will use only a strongly named assembly if it has the exact same version number as the assembly it was compiled with. If the client cannot find a suitable assembly, a TypeLoadException or FileNotFoundException will occur.
Every .NET application defines the components it requires in its manifest, which is a special portion of assembly metadata at the beginning of the compiled file. You can view this information using a handy utility ...