Daniel Finlay

“In software engineering this principle is enshrined as “Postel's law” in honor of Internet pioneer Jon Postel. In RFC760 [97], describing the Internet protocol, he wrote: “The implementation of a protocol must be robust. Each implementation must expect to interoperate with others created by different individuals. While the goal of this specification is to be explicit about the protocol, there is the possibility of differing interpretations. In general, an implementation should be conservative in its sending behavior, and liberal in its receiving behavior.” This is usually summarized as “Be conservative in what you do, be liberal in what you accept from others.”
― Chris Hanson, Software Design for Flexibility: How to Avoid Programming Yourself into a Corner