How to tell if a report has changed?

I'm using Progress 9.1E (it's similar to VB) and Crystal Reports 9.2.

Using the OCX properties of a Crystal Report, is it possible to tell if a report has been changed since a version you know, without simply checking the timestamp?

I want to give reports to customers for them to use, and allow them to modify them if they like...but if they do, I want to have a way of knowing that the report has changed since we gave it to them (in which case we wouldn't provide any support).

I'm thinking along the lines of looking at the count/names of parameter & formula fields, and maybe storing a simple encrypted result of this in a property of the report when it's in our hands. When the report is opened by our software, this value could be checked against the field list again.

Is there a simpler and/or more effective way than this?In Crystal Reports (http://www.shelko.com) there is a modification date and modification time formula under the special fields group in the field explorer window. This will show the date and time that the report was last modified.|||Your 'help' is about as much use as a chocolate fireguard and your sly advertising technique fools no-one|||I think In VB, use File System object to get the last modified date of the file. Search some sample code at www.planet-source-code.com