Sometimes when a library makes a new release, it includes breaking changes to the API. Sometimes, the authors will do this in stages, making use of the Obsolete attribute (for example, .NET 2.0 obsoleted the ConfigurationSettings class in favour of ConfigurationManager) to deprecate a class or method, and indicate what should be used instead.

Sometimes they won't :-)

It'd be cool if it were possible for the library developers to, with ReSharper, to record a refactoring macro or replay-script, which downstream consumers of the library could apply to their product to fix the breaking changes introduced automatically. I've no idea how such a thing might actually be made to work, but, well, it'd be cool, I think.