Compatibility is the compatibility, interconnectivity and interchangeability of different devices, systems and programs from different manufacturers. It is one of the main tasks of national or international standardization efforts. Standards contribute to compatibility, in particular the internationally recognized interfaces and regulations for open networks and systems.
Compatibility may refer to the character set, the code or the storage media, as in the case of data compatibility. It may also refer to the program, processor, or emulation, as in the case of binary compatibility.
A compatibility can be upward or downward. In the case of downward compatibility, it means that a newly developed product, improved software, or new source code will work with the older, existing products or programs. In the case of Upward Compatibility, it means products and software that will be compatible with products and programs developed in the future.