diff --git a/availability/condition/date/classes/condition.php b/availability/condition/date/classes/condition.php
index bdedc31b434de..722b0247be2f6 100644
--- a/availability/condition/date/classes/condition.php
+++ b/availability/condition/date/classes/condition.php
@@ -234,4 +234,68 @@ public function update_after_restore(
         }
         return false;
     }
+
+    /**
+     * Changes all date restrictions on a course by the specified shift amount.
+     * Used by the course reset feature.
+     *
+     * @param int $courseid Course id
+     * @param int $timeshift Offset in seconds
+     */
+    public static function update_all_dates($courseid, $timeshift) {
+        global $DB;
+
+        $modinfo = get_fast_modinfo($courseid);
+        $anychanged = false;
+
+        // Adjust dates from all course modules.
+        foreach ($modinfo->cms as $cm) {
+            if (!$cm->availability) {
+                continue;
+            }
+            $info = new \core_availability\info_module($cm);
+            $tree = $info->get_availability_tree();
+            $dates = $tree->get_all_children('availability_date\condition');
+            $changed = false;
+            foreach ($dates as $date) {
+                $date->time += $timeshift;
+                $changed = true;
+            }
+
+            // Save the updated course module.
+            if ($changed) {
+                $DB->set_field('course_modules', 'availability', json_encode($tree->save()),
+                        array('id' => $cm->id));
+                $anychanged = true;
+            }
+        }
+
+        // Adjust dates from all course sections.
+        foreach ($modinfo->get_section_info_all() as $section) {
+            if (!$section->availability) {
+                continue;
+            }
+
+            $info = new \core_availability\info_section($section);
+            $tree = $info->get_availability_tree();
+            $dates = $tree->get_all_children('availability_date\condition');
+            $changed = false;
+            foreach ($dates as $date) {
+                $date->time += $timeshift;
+                $changed = true;
+            }
+
+            // Save the updated course module.
+            if ($changed) {
+                $DB->set_field('course_sections', 'availability', json_encode($tree->save()),
+                        array('id' => $section->id));
+                $anychanged = true;
+            }
+        }
+
+        // Ensure course cache is cleared if required.
+        if ($anychanged) {
+            rebuild_course_cache($courseid, true);
+        }
+    }
 }
diff --git a/availability/condition/date/tests/condition_test.php b/availability/condition/date/tests/condition_test.php
index 425f1458d1c02..9d32b4374670e 100644
--- a/availability/condition/date/tests/condition_test.php
+++ b/availability/condition/date/tests/condition_test.php
@@ -25,6 +25,7 @@
 defined('MOODLE_INTERNAL') || die();
 
 use availability_date\condition;
+use core_availability\tree;
 
 /**
  * Unit tests for the date condition.
@@ -233,4 +234,53 @@ public function test_get_description() {
         $information = $date->get_standalone_description(true, true, $info);
         $this->assertRegExp('~from.*5 March 2014([^0-9]*)$~', $information);
     }
+
+    /**
+     * Tests the update_all_dates function.
+     */
+    public function test_update_all_dates() {
+        global $DB;
+        $this->resetAfterTest();
+
+        // Create a course with 3 pages.
+        $generator = $this->getDataGenerator();
+        $course = $generator->create_course();
+        $rec = array('course' => $course);
+        $page1 = $generator->get_plugin_generator('mod_page')->create_instance($rec);
+        $page2 = $generator->get_plugin_generator('mod_page')->create_instance($rec);
+        $page3 = $generator->get_plugin_generator('mod_page')->create_instance($rec);
+
+        // Set the availability page 2 to a simple date condition. You can access
+        // it from 1337 onwards.
+        $simplecondition = tree::get_root_json(array(
+                condition::get_json(condition::DIRECTION_FROM, 1337)));
+        $DB->set_field('course_modules', 'availability',
+                json_encode($simplecondition), array('id' => $page2->cmid));
+
+        // Set page 3 to a complex set of conditions including a nested date condition.
+        // You can access it until 1459, *or* after 2810 if you belong to a group.
+        $complexcondition = tree::get_root_json(array(
+                condition::get_json(condition::DIRECTION_UNTIL, 1459),
+                tree::get_nested_json(array(
+                    condition::get_json(condition::DIRECTION_FROM, 2810),
+                    \availability_group\condition::get_json()))),
+                tree::OP_OR);
+        $DB->set_field('course_modules', 'availability',
+                json_encode($complexcondition), array('id' => $page3->cmid));
+
+        // Now use the update_all_dates function to move date forward 100000.
+        condition::update_all_dates($course->id, 100000);
+
+        // Get the expected conditions after adjusting time, and compare to database.
+        $simplecondition->c[0]->t = 101337;
+        $complexcondition->c[0]->t = 101459;
+        $complexcondition->c[1]->c[0]->t = 102810;
+        $this->assertEquals($simplecondition, json_decode(
+                $DB->get_field('course_modules', 'availability', array('id' => $page2->cmid))));
+        $this->assertEquals($complexcondition, json_decode(
+                $DB->get_field('course_modules', 'availability', array('id' => $page3->cmid))));
+
+        // The one without availability conditions should still be null.
+        $this->assertNull($DB->get_field('course_modules', 'availability', array('id' => $page1->cmid)));
+    }
 }
diff --git a/availability/condition/group/classes/condition.php b/availability/condition/group/classes/condition.php
index 2445cdc963f68..a27adaaf89524 100644
--- a/availability/condition/group/classes/condition.php
+++ b/availability/condition/group/classes/condition.php
@@ -229,7 +229,12 @@ public function filter_user_list(array $users, $not, \core_availability\info $in
      * @return stdClass Object representing condition
      */
     public static function get_json($groupid = 0) {
-        return (object)array('type' => 'group', 'id' => (int)$groupid);
+        $result = (object)array('type' => 'group');
+        // Id is only included if set.
+        if ($groupid) {
+            $result->id = (int)$groupid;
+        }
+        return $result;
     }
 
     public function get_user_list_sql($not, \core_availability\info $info, $onlyactive) {
diff --git a/lib/moodlelib.php b/lib/moodlelib.php
index 770658b7478e3..d437e711bfed4 100644
--- a/lib/moodlelib.php
+++ b/lib/moodlelib.php
@@ -5410,6 +5410,11 @@ function reset_course_userdata($data) {
                        WHERE courseid=? AND instance=0";
         $DB->execute($updatesql, array($data->timeshift, $data->courseid));
 
+        // Update any date activity restrictions.
+        if ($CFG->enableavailability) {
+            \availability_date\condition::update_all_dates($data->courseid, $data->timeshift);
+        }
+
         $status[] = array('component' => $componentstr, 'item' => get_string('datechanged'), 'error' => false);
     }