Read this: Changes to DST rules cause problems in existing computer installations. For example, the 2007 change to DST rules in North America required many computer systems to be upgraded, with the greatest impact on email and calendaring programs; the upgrades consumed a significant effort by corporate information technologists.
Now answer this question, if there is an answer (If it cannot be answered, return "unanswerable"): Which professionals bore the brunt of the effort to upgrade systems affected by time changes?
corporate information technologists