It's been a while since I looked at this, but my recollection is that the essential smell is 'distributed transactions with unreliable connectivity and end-of-d

It's been a while since I looked at this, but my recollection is that the essential smell is 'distributed transactions with unreliable connectivity and end-of-day synchronizations are hard'. Works 99.9% of the time; hard to test; impossible to debug failures after the fact without access to paper receipts or customers. This is compounded by the system being delivered and operated by an outsourced vendor which doesn't have incentives that are aligned with those of the outsourcing organization, and the arms-length relationship to the sub-postmasters.