I'm sure it sucks that it's "four digits only" but the air travel industry isn't immune from changing specifications. I believe ancient cultures called this software maintenance.
Yes, they've changed specifications before. Y2K being one example. Artificial seems strong though. I was trying to explain that a single airline can't fix this solely in-house. It would have to be an industry change across airlines, government agencies, third party vendors, etc. So it's not artificial, but it's not trivial either.
