Ability to have CHANGED operator for (specifically configured) custom fields

JIRA helps us as organisation in giving insight and overview to some formal internal procedures. In this way JIRA contributes to "in control" auditing.

The CHANGED operator is very useful in this respect. So useful that we would very much like to apply this to one or two other fields. It would be very useful to have this on a field containing versions.

Request: an option by definition of a new custion field of including history so that the field can be used with the operators WAS and CHANGED