...
- Create a Dummy sprint (with start date and end date)
- put a single "bogus" issue in the new sprint
- Edit the issue's sprint field "edit screen" (where I display the Greenhopper Sprint Field) for the bogus issue
- Update the value from the Greenhopper Sprint Field (its a serial number)
- search for all the issues in the closed sprint (based on the Greenhopper Sprint Field)
- Perform a bulk change on the returned issues, updating the Greenhopper Sprint Field from their current ID(the old sprint ID), to the ID of the new sprint
- removed remove the bogus issue you added to the new sprint (whose purpose was to provide me with the new sprint ID)
- renamed rename the new sprint to match the old one.
- updated update every filter which references the sprint ID
...