Backward compatibility is the capability of interoperating with older systems. In telecommunications and computing, a product or technology is backward or downward compatible if it can work with input generated by an older product or technology. If products designed for the new standard can receive, read, view or play older standards or formats, then the product is said to be backward-compatible; examples of such a standard include data formats and communication protocols. The reverse is forward compatibility, which implies that old devices allow data formats generated by new devices, perhaps without supporting all new features. A standard supports forward compatibility if older product versions can receive, read, view, or play the new standard. For example, the introduction of FM stereo transmission allowed backward compatibility since new FM radio receivers could receive monaural signals generated by old transmitters. It also allowed forward compatibility, since old monaural FM radio receivers could still receive a signal from a new transmitter. In programming languages, backward compatibility refers to the ability of a compiler for version N of the language to accept programs or data that worked under version N - 1. By this definition, if previous versions were also backward compatible, which is often the case, then, by induction, version N will also accept input that worked under any prior version after, and including, the latest one that was not backward compatible. However, in practice, features are often deprecated and support is dropped in a later release, which is yet thought of as backward compatible. Backward compatibility is the capability o
