It's not enough to get organizational software compliant. Decision support software must also be compliant.
Decision support software is the in-house decision-assisting software that people in an organization have created to help them make decisions. Very often, it is independent of the IT (information technology) division. Most IT departments do not consider it when designing their Year 2000 repair projects.
The data produced by this software will be wrong. But users won't know the data are wrong. They will use it. It's called the Year 2001 Problem.
This is from ZD NET.