Queries regarding Extended Workflow Notifications SWNCONFIG

Hi Experts,

I have gone through the material available on SCN regarding extended workflow notifications, however i have specific queries as follows:

1. Whats the use of 'Delete Old notifications' in Filter Basic data for Extended notifications for Workflows in SAP.

2. Whats the use of Assigned main filter ?

3. Is there a way by which i can restrict the selection of workitems based on workitem creation time stamp?

4. For sending a reminder email after 2 days, i have configured the REMINDER_DAYS as 2 days; should be filter parameter 'DELTA' be set as 'X' or is it fine if i     leave it blank?

Thanks you.

Regards,

Santhosh.