At the heart of Semantic Versioning is a distinction between incompatible API changes (“breaking” changes) and backwards-compatible API changes (“non-breaking” changes). When you make a change that could break existing code, you must increment the MAJOR component of its version number. Since failing to do this correctly may cause builds or tests to fail seemingly-spontaneously, knowing what kinds of changes are breaking and which are not is crucial to good crate hygiene.
