You may want to change the unique code of your old marking periods to avoid having old data in your new terms.
It is technically possible to edit the codes for marking periods where grades are already submitted. However, it is not advisable to change the codes for the marking periods that have already closed because the grades have already been imported and the data is already in your SIS.
Unfortunately, if the import data from those terms contained past records, the school has to filter them out during the import to their SIS and the School Loop support team will not be able to provide assistance as we are not equipped to support SIS-related concerns. This is to avoid any potential sync issues that could happen due to the difference in the marking period.
Since the term codes are used as identifiers when saving the grades submitted by teachers on our database, the submissions for the old marking period were saved under the current term codes. By changing these codes, the submissions will be removed and the reconfigured terms will have empty data. If your SIS still checks and syncs data from these previous quarters, the data in your SIS could potentially be deleted.
In case you already modified them, you can still restore them by changing the code back to the original one.