Testing the patch and the upgrade script Before the patch Navigate to Site administration > Server > Tasks > Scheduled tasks. Disable "Prepare submissions for annotation" scheduled task. Create an assignment with  File submissions  and  Annotate PDF  enabled. As a student submit a submission with a file. Check the  mdl_assignfeedback_editpdf_queue table to have a record for the submission. mysql> select * from mdl_assignfeedback_editpdf_queue; +----+--------------+-------------------+----------------------+ | id | submissionid | submissionattempt | attemptedconversions | +----+--------------+-------------------+----------------------+ | 5 | 6 | 0 | 0 | +----+--------------+-------------------+----------------------+ 1 row in set ( 0.00 sec) As a teacher navigate to the grading page. Confirm , that the submission is converted and displayed. Check the  mdl_assignfeedback_editpdf_queue table and confirm , that the record still exists. mysql> select * from mdl_assignfeedback_editpdf_queue; +----+--------------+-------------------+----------------------+ | id | submissionid | submissionattempt | attemptedconversions | +----+--------------+-------------------+----------------------+ | 5 | 6 | 0 | 0 | +----+--------------+-------------------+----------------------+ 1 row in set ( 0.00 sec) After the patch With the patch applied, run the upgrade script. Check the  mdl_assignfeedback_editpdf_queue table and confirm , that the record was deleted. mysql> select * from mdl_assignfeedback_editpdf_queue; Empty set ( 0.00 sec) Create new assignment with  File submissions  and  Annotate PDF  enabled. As a student submit a submission with a file. Check the  mdl_assignfeedback_editpdf_queue table to have a record for the submission. mysql> select * from mdl_assignfeedback_editpdf_queue; +----+--------------+-------------------+----------------------+ | id | submissionid | submissionattempt | attemptedconversions | +----+--------------+-------------------+----------------------+ | 6 | 7 | 0 | 0 | +----+--------------+-------------------+----------------------+ 1 row in set ( 0.00 sec) As a teacher navigate to the grading page. Confirm , that the submission is converted and displayed. Check the  mdl_assignfeedback_editpdf_queue table and confirm , that the record was deleted. mysql> select * from mdl_assignfeedback_editpdf_queue; Empty set ( 0.00 sec)