What quality allows an older system to work effectively with a newer system?

The quality that enables an older system to work effectively with a newer system is referred to as backward compatibility. This concept involves the newer system being designed in such a way that it can still interact with and support the functionalities of the older system. This is particularly important in software and hardware development, as it ensures that users can upgrade to new versions without losing access to features or data from previous versions.

When a new system maintains backward compatibility, it allows users to continue using their existing applications or tools without needing to completely overhaul their systems. This is critical in maintaining continuity and reducing disruption for users who might rely on legacy systems.

Forward compatibility, on the other hand, involves a system's ability to accept input intended for a future version of itself, which does not typically relate to the interaction with older systems. Interoperability refers to the ability of different systems or components to work together, but it does not specifically guarantee that an older system can function seamlessly within a newer environment. System integration involves combining different subsystems into a unified whole, but this doesn't inherently mean that older systems will function effectively with newer ones without the specific quality of backward compatibility.