diff --git a/mod/assign/locallib.php b/mod/assign/locallib.php
index 4890e7a623a..791734e0347 100644
--- a/mod/assign/locallib.php
+++ b/mod/assign/locallib.php
@@ -2663,7 +2663,7 @@ class assign {
             $plugins = $this->get_submission_plugins();
             foreach ($plugins as $plugin) {
                 if ($plugin->is_enabled() && $plugin->is_visible()) {
-                    $plugin->submit_for_grading();
+                    $plugin->submit_for_grading($submission);
                 }
             }
 
@@ -3288,6 +3288,13 @@ class assign {
         $submission->status = ASSIGN_SUBMISSION_STATUS_DRAFT;
         $this->update_submission($submission, false);
 
+        // Give each submission plugin a chance to process the reverting to draft.
+        $plugins = $this->get_submission_plugins();
+        foreach ($plugins as $plugin) {
+            if ($plugin->is_enabled() && $plugin->is_visible()) {
+                $plugin->revert_to_draft($submission);
+            }
+        }
         // update the modified time on the grade (grader modified)
         $grade = $this->get_user_grade($userid, true);
         $this->update_grade($grade);
@@ -3315,6 +3322,15 @@ class assign {
             $userid = required_param('userid', PARAM_INT);
         }
 
+        // Give each submission plugin a chance to process the locking.
+        $plugins = $this->get_submission_plugins();
+        $submission = $this->get_user_submission($userid, false);
+        foreach ($plugins as $plugin) {
+            if ($plugin->is_enabled() && $plugin->is_visible()) {
+                $plugin->lock($submission);
+            }
+        }
+
         $grade = $this->get_user_grade($userid, true);
         $grade->locked = 1;
         $grade->grader = $USER->id;
@@ -3342,6 +3358,15 @@ class assign {
             $userid = required_param('userid', PARAM_INT);
         }
 
+        // Give each submission plugin a chance to process the locking.
+        $plugins = $this->get_submission_plugins();
+        $submission = $this->get_user_submission($userid, false);
+        foreach ($plugins as $plugin) {
+            if ($plugin->is_enabled() && $plugin->is_visible()) {
+                $plugin->unlock($submission);
+            }
+        }
+
         $grade = $this->get_user_grade($userid, true);
         $grade->locked = 0;
         $grade->grader = $USER->id;
diff --git a/mod/assign/submissionplugin.php b/mod/assign/submissionplugin.php
index 29462c9ee55..3257be0138e 100644
--- a/mod/assign/submissionplugin.php
+++ b/mod/assign/submissionplugin.php
@@ -69,9 +69,38 @@ abstract class assign_submission_plugin extends assign_plugin {
 
     /**
      * Carry out any extra processing required when the work is submitted for grading
+     *
+     * @param stdClass $submission - assign_submission data
      * @return void
      */
-    public function submit_for_grading() {
+    public function submit_for_grading(stdClass $submission) {
+    }
+
+    /**
+     * Carry out any extra processing required when the work is locked.
+     *
+     * @param stdClass $submission - assign_submission data
+     * @return void
+     */
+    public function lock(stdClass $submission) {
+    }
+
+    /**
+     * Carry out any extra processing required when the work is unlocked.
+     *
+     * @param stdClass $submission - assign_submission data
+     * @return void
+     */
+    public function unlock(stdClass $submission) {
+    }
+
+    /**
+     * Carry out any extra processing required when the work reverted to draft.
+     *
+     * @param stdClass $submission - assign_submission data
+     * @return void
+     */
+    public function revert_to_draft(stdClass $submission) {
     }
 
 }