XML Forms

This can be achieved through the Time-based Publishing service provided by SAP. To make sure the service is active for your repository, go to System Administration > System Configuration > Knowledge Management > Content Management > Repository Managers > CM Repository (if that's the kind of repository you're working in). Then select your repository and make sure that 'tbp' is in the list of Repository Services assigned. If not, assign that service and restart the portal.

Then, within KM Content, enter the Details menu of the folder within that repository for which you'd like this service activated, then go to Settings > Lifetime and click the 'Enable Time-Dependent Publishing' button. This will activate the service for that folder.

Then in your XML form, you can provide the Lifetime properties "Valid From" and/or "Valid To" to specify when a message should be active, and when it should expire. At that point, anyone who has read access to that folder would only see the messages that are within these active dates.

Hope this helps! For more information, see SAP's Lifetime of Documents documentation.