I'm skeptical of the idea of the IRS moving to a contemporary platform of any kind. They have 50 years into the current configuration, with no signs it will be

I'm skeptical of the idea of the IRS moving to a contemporary platform of any kind. They have 50 years into the current configuration, with no signs it will be replaced soon. On the time scale of decades, what platforms have proven to be stable and backwards compatible over that time frame? I mention the decades time scale, because I'm not at all confident that the next revision (after the one that hasn't yet happened) of the IRS platform will take anything less than another 50 years, and in that time, almost everything current today will look like a flash in the pan. I think they'd be better off moving up one step in the abstraction layer with something written in COBOL for the backend, and some kind of service layer whose clients can be updated over time as need allows. If they can de-couple and modularize as as possible, it will make future upgrades more manageable. In many respects their data workload pales in comparison to what used to be called "big data". Their system is more analogous to airline scheduling in the need for availability, correctness, and longevity. They have to take a very conservative approach. Even if they were spending tens of millions a year on maintenance, that's a better option than the risk of a major downtime during tax season.