Developing a L2 stack is challenging. It is about balancing the certificabilityand the flexibility of the solution.
Certificability means that the stack shall not be altered once it has been TA approved. L2 behaviors shall be black-boxed so the integrators have not to deal with that level of complexitiy. Developing at the L3 shall preserve L2 from regression.
Flexibilitymeans that stack shall be adaptable to any merchant/acquirer contexts. The regional nature of the payment is not well addressed by EMVCo specifications:
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