For the Y2K, we weren't allowed to change any of the original code running on the AS/400. That code was always off-limit, and had existed since the 1970s as far as I know.

We created an intermediate tool that would look at transactions going into and out of the database.

When data was coming out, we'd convert the dates to 4-digit years. Then when data was going in, we'd convert 4-digit years back to 2-digit years.

I have no idea if 26 years later that is still in place. I suspect so. But the thought that banks will authorize AI and "vibe coding" to magically replace all this off-limit code running on the back end is hard to believe.