SE RDS v4.10: Adding units of MONTH to a DATETIME

Hi, I wondered if anybody has come across this one before: I am using Informix SE RDS v4.10 and want to use a datetime variable to determine a date 6 months forward of the current system date. I tried using something like: let new_date = today + 6 units month Unfortunately, for a date such as 31/10/1995, the above statement sets new_date = 31/04/1995 and the program, obviously, reports an error. Has this problem been fixed in any later releases of RDS ? Suggestions greatly appreciated. Keith