diff --git a/classes/output/combined/renderer.php b/classes/output/combined/renderer.php
index a4ea22e..07d7622 100644
--- a/classes/output/combined/renderer.php
+++ b/classes/output/combined/renderer.php
@@ -36,9 +36,27 @@
 
 defined('MOODLE_INTERNAL') || die();
 
-require_once($CFG->dirroot . '/question/type/combined/renderer.php');
-require_once($CFG->dirroot . '/question/type/combined/combinable/gapselect/renderer.php');
-require_once($CFG->dirroot . '/question/type/oumultiresponse/combinable/renderer.php');
+// Work-around when the class does not exist.
+if (class_exists('\qtype_combined_renderer')) {
+    class_alias('\qtype_combined_renderer', '\qtype_combined_renderer_alias');
+    require_once($CFG->dirroot . '/question/type/combined/renderer.php');
+} else {
+    class_alias('\qtype_renderer', '\qtype_combined_renderer_alias');
+}
+
+if (class_exists('\qtype_oumultiresponse_embedded_renderer')) {
+    class_alias('\qtype_oumultiresponse_embedded_renderer', '\qtype_oumultiresponse_embedded_renderer_alias');
+    require_once($CFG->dirroot . '/question/type/oumultiresponse/combinable/renderer.php');
+} else {
+    class_alias('\qtype_renderer', '\qtype_oumultiresponse_embedded_renderer_alias');
+}
+
+if (class_exists('\qtype_combined_gapselect_embedded_renderer')) {
+    class_alias('\qtype_combined_gapselect_embedded_renderer', '\qtype_combined_gapselect_embedded_renderer_alias');
+    require_once($CFG->dirroot . '/question/type/combined/combinable/gapselect/renderer.php');
+} else {
+    class_alias('\qtype_renderer', '\qtype_combined_gapselect_embedded_renderer_alias');
+}
 
 /**
  * The override qtype_combined_renderer for the quiz_answersheets module.
@@ -46,7 +64,7 @@
  * @copyright  2020 The Open University
  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
-class qtype_combined_override_renderer extends \qtype_combined_renderer {
+class qtype_combined_override_renderer extends \qtype_combined_renderer_alias {
 
     /**
      * The code was copied from question/type/combined/renderer.php, with modifications.
@@ -158,7 +176,7 @@ private function get_embedded_renderer(qtype_combined_combinable_type_base $ques
  *
  * @package quiz_answersheets\output\combined
  */
-class qtype_oumultiresponse_embedded_override_renderer extends \qtype_oumultiresponse_embedded_renderer {
+class qtype_oumultiresponse_embedded_override_renderer extends \qtype_oumultiresponse_embedded_renderer_alias {
 
     /**
      * The code was copied from question/type/oumultiresponse/combinable/renderer.php, with modifications.
@@ -261,7 +279,7 @@ public function subquestion(question_attempt $qa, question_display_options $opti
  *
  * @package quiz_answersheets\output\combined
  */
-class qtype_combined_gapselect_embedded_override_renderer extends \qtype_combined_gapselect_embedded_renderer {
+class qtype_combined_gapselect_embedded_override_renderer extends \qtype_combined_gapselect_embedded_renderer_alias {
 
     /**
      * Render the sub question.
diff --git a/classes/output/oumultiresponse/renderer.php b/classes/output/oumultiresponse/renderer.php
index 473faf1..9af2a48 100644
--- a/classes/output/oumultiresponse/renderer.php
+++ b/classes/output/oumultiresponse/renderer.php
@@ -31,7 +31,13 @@
 
 defined('MOODLE_INTERNAL') || die();
 
-require_once($CFG->dirroot . '/question/type/oumultiresponse/renderer.php');
+// Work-around when the class does not exist.
+if (class_exists('\qtype_oumultiresponse_renderer')) {
+    class_alias('\qtype_oumultiresponse_renderer', '\qtype_oumultiresponse_renderer_alias');
+    require_once($CFG->dirroot . '/question/type/oumultiresponse/renderer.php');
+} else {
+    class_alias('\qtype_renderer', '\qtype_oumultiresponse_renderer_alias');
+}
 
 /**
  * The override qtype_oumultiresponse_renderer for the quiz_answersheets module.
@@ -39,7 +45,7 @@
  * @copyright  2020 The Open University
  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
-class qtype_oumultiresponse_override_renderer extends \qtype_oumultiresponse_renderer {
+class qtype_oumultiresponse_override_renderer extends \qtype_oumultiresponse_renderer_alias {
 
     /**
      * The code was copied from question/type/oumultiresponse/renderer.php, with modifications.
diff --git a/classes/output/pmatch/renderer.php b/classes/output/pmatch/renderer.php
index 963b327..aaff157 100644
--- a/classes/output/pmatch/renderer.php
+++ b/classes/output/pmatch/renderer.php
@@ -29,7 +29,13 @@
 use qtype_pmatch_question;
 use question_display_options;
 
-require_once($CFG->dirroot . '/question/type/pmatch/renderer.php');
+// Work-around when the class does not exist.
+if (class_exists('\qtype_pmatch_renderer')) {
+    class_alias('\qtype_pmatch_renderer', '\qtype_pmatch_renderer_alias');
+    require_once($CFG->dirroot . '/question/type/pmatch/renderer.php');
+} else {
+    class_alias('\qtype_renderer', '\qtype_pmatch_renderer_alias');
+}
 
 /**
  * The override qtype_pmatch_renderer for the quiz_answersheets module.
@@ -37,7 +43,7 @@
  * @copyright  2020 The Open University
  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
-class qtype_pmatch_override_renderer extends \qtype_pmatch_renderer {
+class qtype_pmatch_override_renderer extends \qtype_pmatch_renderer_alias {
 
     public function question_tests_link(qtype_pmatch_question $question, question_display_options $options) {
         // Do not show the question test link.
diff --git a/classes/output/recordrtc/renderer.php b/classes/output/recordrtc/renderer.php
index 8ccf5b1..3f7a124 100644
--- a/classes/output/recordrtc/renderer.php
+++ b/classes/output/recordrtc/renderer.php
@@ -32,7 +32,13 @@
 use question_attempt;
 use question_display_options;
 
-require_once($CFG->dirroot . '/question/type/recordrtc/renderer.php');
+// Work-around when the class does not exist.
+if (class_exists('\qtype_recordrtc_renderer')) {
+    class_alias('\qtype_recordrtc_renderer', '\qtype_recordrtc_renderer_alias');
+    require_once($CFG->dirroot . '/question/type/recordrtc/renderer.php');
+} else {
+    class_alias('\qtype_renderer', '\qtype_recordrtc_renderer_alias');
+}
 
 /**
  * The override qtype_recordrtc_renderer for the quiz_answersheets module.
@@ -41,7 +47,7 @@
  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
 
-class qtype_recordrtc_override_renderer extends \qtype_recordrtc_renderer {
+class qtype_recordrtc_override_renderer extends \qtype_recordrtc_renderer_alias {
 
     protected function no_recording_message(): string {
         $output = '';
diff --git a/classes/output/stack/renderer.php b/classes/output/stack/renderer.php
index 3693ada..62e852f 100644
--- a/classes/output/stack/renderer.php
+++ b/classes/output/stack/renderer.php
@@ -35,7 +35,13 @@
 use stack_maths;
 use stack_utils;
 
-require_once($CFG->dirroot . '/question/type/stack/renderer.php');
+// Work-around when the class does not exist.
+if (class_exists('\qtype_stack_renderer')) {
+    class_alias('\qtype_stack_renderer', '\qtype_stack_renderer_alias');
+    require_once($CFG->dirroot . '/question/type/stack/renderer.php');
+} else {
+    class_alias('\qtype_renderer', '\qtype_stack_renderer_alias');
+}
 
 /**
  * The override qtype_stack_renderer for the quiz_answersheets module.
@@ -43,7 +49,7 @@
  * @copyright  2020 The Open University
  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
-class qtype_stack_override_renderer extends \qtype_stack_renderer {
+class qtype_stack_override_renderer extends \qtype_stack_renderer_alias {
 
     protected function question_tests_link(qtype_stack_question $question, question_display_options $options) {
         // Do not show the question test link.