1. A method for processing exceptions produced by an application program, said method comprising the steps of: a) identifying in an exception handler module executing in memory by a processor of a computer, a first set of exceptions produced by both a first version of a first application program and by a second version of said first application program subsequent to said first version; b) identifying a second set of exceptions produced by said second version of said first application program but not by said first version; c) receiving an original exception from said second set of exceptions from said second version of said first application program; d) substituting said original exception for a predetermined substitute exception from said first set of exceptions; and e) appending an identification of said original exception as metadata to said substitute exception so as to enable a second application program receiving said substitute exception but not arranged to process said second set of exceptions to process said substitute exception and to enable a third application program receiving said substitute exception and arranged to process members of said second set of exceptions to extract and process said original exception.