DBCENTURY...DBDATE...DATETIME...let's be clear about this

Hi All, Sorry to bring up this issue again but I seek to clarify the Year 2000 aspects of our Informix products. We have SE V4.00.UE2, RDS V4.00.UC1, SQL V4.00.UE1. Users enter dates in the YY format...no century entered and all dates are held in the database of type DATE. We are moving from AIX 3.1 to AIX 4.2 for year 2000 compliancy which necessitates the need to re-license our Informix products. As part of the re-licensing, only the SE will be upgraded to V5. I don't believe that with a V5 SE and V4 products we will have the DBCENTURY variable available to us. Would I be correct in saying that without the DBCENTURY environment variable then regardless of whether the user enters the century postion of a date then we still have a problem. Indeed, is it a necessity to have DBCENTURY to be Year 2000 compliant? Any views/comments would be very welcome. Cheers, Ian. Tedious 'office speak' part 3: "Let's go scuba in the think tank."