Breaking (Compatibility)

In software and protocol design, "breaking" describes a change that stops existing users, integrations or data from working as before, usually called a breaking change. Examples include removing a field from an API, changing a message format or renaming a function that other programs rely on. Breaking changes are the opposite of backward compatibility. Software projects often signal them by raising the major version number, as in semantic versioning, and announce deprecation periods so users can adapt. In payments, a breaking change to a bank or card network's message format can cause failed transactions if partners do not update. In blockchains, a hard fork is a breaking change to consensus rules, whereas a soft fork is designed not to break older nodes. Also see Beta Version (Software).