The ASM Support System is extensible. This means that new features can be added. This places requirements on the design. It must be adaptable over time and remain interoperable between two major versions. Incompatibility between software versions is inevitable as systems mature and improve over their lifetime, but it is a priority to minimise disruption between upgrades. Maintaining a stable interface between two major versions would allow the wider user community the opportunity to upgrade their software at the most suitable time, rather than enforcing the need for updating as soon as a new release becomes available