diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 00000000..cc4ee16c
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,122 @@
+name: Moodle plugin CI
+on: [push, pull_request]
+
+jobs:
+  test:
+    runs-on: 'ubuntu-latest'
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - php: '7.4'
+            moodle-branch: 'MOODLE_311_STABLE'
+            database: 'mariadb'
+            node: '14.15.0'
+          - php: '7.3'
+            moodle-branch: 'MOODLE_310_STABLE'
+            database: 'mariadb'
+            node: '14.15.0'
+          - php: '7.4'
+            moodle-branch: 'MOODLE_311_STABLE'
+            database: 'pgsql'
+            node: '14.15.0'
+          - php: '7.3'
+            moodle-branch: 'MOODLE_310_STABLE'
+            database: 'pgsql'
+            node: '14.15.0'
+
+    services:
+      postgres:
+        image: postgres
+        env:
+          POSTGRES_USER: 'postgres'
+          POSTGRES_HOST_AUTH_METHOD: 'trust'
+        options: >-
+          --health-cmd pg_isready
+          --health-interval 10s
+          --health-timeout 5s
+          --health-retries 3
+        ports:
+          - 5432:5432
+
+      mariadb:
+        image: mariadb
+        env:
+          MYSQL_USER: 'root'
+          MYSQL_ALLOW_EMPTY_PASSWORD: "true"
+        ports:
+          - 3306:3306
+        options: --health-cmd="mysqladmin ping" --health-interval 10s --health-timeout 5s --health-retries 3
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+        with:
+          path: plugin
+
+      - name: Install node
+        uses: actions/setup-node@v1
+        with:
+          node-version: ${{ matrix.node }}
+
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: ${{ matrix.php }}
+          extensions: zip, gd, mbstring, pgsql, mysqli
+
+      - name: Deploy moodle-plugin-ci
+        run: |
+          composer create-project -n --no-dev --prefer-dist moodlehq/moodle-plugin-ci ci ^3
+          # Add dirs to $PATH
+          echo $(cd ci/bin; pwd) >> $GITHUB_PATH
+          echo $(cd ci/vendor/bin; pwd) >> $GITHUB_PATH
+          # PHPUnit depends on en_AU.UTF-8 locale
+          sudo locale-gen en_AU.UTF-8
+      - name: Install Moodle
+        # Need explicit IP to stop mysql client fail on attempt to use unix socket.
+        run: moodle-plugin-ci install --plugin ./plugin --db-host=127.0.0.1
+        env:
+          DB: ${{ matrix.database }}
+          MOODLE_BRANCH: ${{ matrix.moodle-branch }}
+          IGNORE_NAMES: 'mobile_*.mustache'
+
+      - name: phplint
+        if: ${{ always() }}
+        run: moodle-plugin-ci phplint
+
+      - name: phpcpd
+        if: ${{ always() }}
+        run: moodle-plugin-ci phpcpd || true
+
+      - name: phpmd
+        if: ${{ always() }}
+        run: moodle-plugin-ci phpmd
+
+      - name: codechecker
+        if: ${{ always() }}
+        run: moodle-plugin-ci codechecker
+
+      - name: validate
+        if: ${{ always() }}
+        run: moodle-plugin-ci validate
+
+      - name: savepoints
+        if: ${{ always() }}
+        run: moodle-plugin-ci savepoints
+
+      - name: mustache
+        if: ${{ always() }}
+        run: moodle-plugin-ci mustache
+
+      - name: grunt
+        if: ${{ always() }}
+        run: moodle-plugin-ci grunt
+
+      - name: phpunit
+        if: ${{ always() }}
+        run: moodle-plugin-ci phpunit
+
+      - name: behat
+        if: ${{ always() }}
+        run: moodle-plugin-ci behat --profile chrome
\ No newline at end of file
diff --git a/backup/moodle2/backup_questionnaire_activity_task.class.php b/backup/moodle2/backup_questionnaire_activity_task.class.php
index f1473e21..33e4e2aa 100644
--- a/backup/moodle2/backup_questionnaire_activity_task.class.php
+++ b/backup/moodle2/backup_questionnaire_activity_task.class.php
@@ -53,7 +53,7 @@ protected function define_my_steps() {
      * Code the transformations to perform in the activity in
      * order to get transportable (encoded) links
      */
-    static public function encode_content_links($content) {
+    public static function encode_content_links($content) {
         global $CFG;
 
         $base = preg_quote($CFG->wwwroot, "/");
diff --git a/backup/moodle2/backup_questionnaire_stepslib.php b/backup/moodle2/backup_questionnaire_stepslib.php
index f767068d..5c25e689 100644
--- a/backup/moodle2/backup_questionnaire_stepslib.php
+++ b/backup/moodle2/backup_questionnaire_stepslib.php
@@ -190,10 +190,10 @@ protected function define_structure() {
             // Define id annotations.
             $response->annotate_ids('user', 'userid');
         }
-        // Define file annotations
+        // Define file annotations.
         $questionnaire->annotate_files('mod_questionnaire', 'intro', null); // This file area hasn't itemid.
 
-        $survey->annotate_files('mod_questionnaire', 'info', 'id'); // By survey->id
+        $survey->annotate_files('mod_questionnaire', 'info', 'id'); // By survey->id.
         $survey->annotate_files('mod_questionnaire', 'thankbody', 'id'); // By survey->id.
 
         $question->annotate_files('mod_questionnaire', 'question', 'id'); // By question->id.
diff --git a/backup/moodle2/restore_questionnaire_activity_task.class.php b/backup/moodle2/restore_questionnaire_activity_task.class.php
index da6b7d50..60f28beb 100644
--- a/backup/moodle2/restore_questionnaire_activity_task.class.php
+++ b/backup/moodle2/restore_questionnaire_activity_task.class.php
@@ -51,7 +51,7 @@ protected function define_my_steps() {
      * Define the contents in the activity that must be
      * processed by the link decoder
      */
-    static public function define_decode_contents() {
+    public static function define_decode_contents() {
         $contents = array();
 
         $contents[] = new restore_decode_content('questionnaire', array('intro'), 'questionnaire');
@@ -66,7 +66,7 @@ static public function define_decode_contents() {
      * Define the decoding rules for links belonging
      * to the activity to be executed by the link decoder
      */
-    static public function define_decode_rules() {
+    public static function define_decode_rules() {
         $rules = array();
 
         $rules[] = new restore_decode_rule('QUESTIONNAIREVIEWBYID', '/mod/questionnaire/view.php?id=$1', 'course_module');
@@ -82,7 +82,7 @@ static public function define_decode_rules() {
      * questionnaire logs. It must return one array
      * of {@link restore_log_rule} objects
      */
-    static public function define_restore_log_rules() {
+    public static function define_restore_log_rules() {
         $rules = array();
 
         $rules[] = new restore_log_rule('questionnaire', 'add', 'view.php?id={course_module}', '{questionnaire}');
@@ -105,7 +105,7 @@ static public function define_restore_log_rules() {
      * by the restore final task, but are defined here at
      * activity level. All them are rules not linked to any module instance (cmid = 0)
      */
-    static public function define_restore_log_rules_for_course() {
+    public static function define_restore_log_rules_for_course() {
         $rules = array();
 
         // Fix old wrong uses (missing extension).
diff --git a/classes/edit_question_form.php b/classes/edit_question_form.php
index 71f65a41..eb5d4c49 100644
--- a/classes/edit_question_form.php
+++ b/classes/edit_question_form.php
@@ -46,12 +46,12 @@ public function definition() {
             $question->required = $SESSION->questionnaire->required;
         }
         if (!isset($question->type_id)) {
-            print_error('undefinedquestiontype', 'questionnaire');
+            throw new \moodle_exception('undefinedquestiontype', 'mod_questionnaire');
         }
 
         // Each question can provide its own form elements to the provided form, or use the default ones.
         if (!$question->edit_form($this, $questionnaire)) {
-            print_error("Question type had an unknown error in the edit_form method.");
+            throw new \moodle_exception('Question type had an unknown error in the edit_form method.', 'mod_questionnaire');
         }
     }
 
diff --git a/classes/question/check.php b/classes/question/check.php
index 39fce792..54533ed3 100644
--- a/classes/question/check.php
+++ b/classes/question/check.php
@@ -269,7 +269,7 @@ public function supports_mobile() {
      */
     protected function form_preprocess_choicedata($formdata) {
         if (empty($formdata->allchoices)) {
-            print_error(get_string('enterpossibleanswers', 'questionnaire'));
+            throw new \moodle_exception('enterpossibleanswers', 'mod_questionnaire');
         } else {
             // Sanity checks for min and max checked boxes.
             $allchoices = $formdata->allchoices;
diff --git a/classes/question/choice/choice.php b/classes/question/choice.php
similarity index 96%
rename from classes/question/choice/choice.php
rename to classes/question/choice.php
index 9184f2fb..f70733e2 100644
--- a/classes/question/choice/choice.php
+++ b/classes/question/choice.php
@@ -23,7 +23,7 @@
  * @copyright 2019, onwards Poet
  */
 
-namespace mod_questionnaire\question\choice;
+namespace mod_questionnaire\question;
 defined('MOODLE_INTERNAL') || die();
 
 class choice {
@@ -132,7 +132,7 @@ public function delete_from_db() {
      * @param string $content
      * @return bool
      */
-    static public function content_is_other_choice($content) {
+    public static function content_is_other_choice($content) {
         return (strpos($content, '!other') === 0);
     }
 
@@ -152,7 +152,7 @@ public function is_other_choice() {
      * @return string | bool
      * @throws \coding_exception
      */
-    static public function content_other_choice_display($content) {
+    public static function content_other_choice_display($content) {
         if (!self::content_is_other_choice($content)) {
             return false;
         }
@@ -197,7 +197,7 @@ public function is_named_degree_choice() {
      * @param int $choiceid
      * @return string
      */
-    static public function id_other_choice_name($choiceid) {
+    public static function id_other_choice_name($choiceid) {
         return 'o' . $choiceid;
     }
 
diff --git a/classes/question/drop.php b/classes/question/drop.php
index 00789424..9efb1eb8 100644
--- a/classes/question/drop.php
+++ b/classes/question/drop.php
@@ -25,7 +25,7 @@
 namespace mod_questionnaire\question;
 defined('MOODLE_INTERNAL') || die();
 use \html_writer;
-use mod_questionnaire\question\choice\choice;
+use mod_questionnaire\question\choice;
 
 class drop extends question {
 
diff --git a/classes/question/question.php b/classes/question/question.php
index b3270f96..cf9c38a4 100644
--- a/classes/question/question.php
+++ b/classes/question/question.php
@@ -188,7 +188,7 @@ abstract public function helpname();
      * @var object $context The context for the question.
      * @return A question object.
      */
-    static public function question_builder($qtype, $qdata = null, $context = null) {
+    public static function question_builder($qtype, $qdata = null, $context = null) {
         $qclassname = '\\mod_questionnaire\\question\\'.self::qtypename($qtype);
         $qid = 0;
         if (!empty($qdata) && is_array($qdata)) {
@@ -204,7 +204,7 @@ static public function question_builder($qtype, $qdata = null, $context = null)
      * @param $qtype
      * @return string
      */
-    static public function qtypename($qtype) {
+    public static function qtypename($qtype) {
         if (array_key_exists($qtype, self::$qtypenames)) {
             return self::$qtypenames[$qtype];
         } else {
@@ -216,7 +216,7 @@ static public function qtypename($qtype) {
      * Return all of the different question type names.
      * @return array
      */
-    static public function qtypenames() {
+    public static function qtypenames() {
         return self::$qtypenames;
     }
 
@@ -235,7 +235,7 @@ private function get_choices() {
 
         if ($choices = $DB->get_records('questionnaire_quest_choice', ['question_id' => $this->id], 'id ASC')) {
             foreach ($choices as $choice) {
-                $this->choices[$choice->id] = choice\choice::create_from_data($choice);
+                $this->choices[$choice->id] = \mod_questionnaire\question\choice::create_from_data($choice);
             }
         } else {
             $this->choices = [];
@@ -704,7 +704,7 @@ public function delete_choice($choice) {
         } else {
             $cid = $choice->id;
         }
-        if (\mod_questionnaire\question\choice\choice::delete_from_db_by_id($cid)) {
+        if (\mod_questionnaire\question\choice::delete_from_db_by_id($cid)) {
             unset($this->choices[$cid]);
         } else {
             $retvalue = false;
@@ -894,7 +894,7 @@ public function questionstart_survey_display($qnum, $response=null) {
         if ($response instanceof \mod_questionnaire\responsetype\response\response) {
             $skippedquestion = !isset($response->answers[$this->id]);
         } else {
-            $skippedquestion = !empty($response) && !array_key_exists('q'.$this->id, $response);
+            $skippedquestion = !empty($response) && !isset($response->{'q'.$this->id});
         }
 
         // If we are on report page and this questionnaire has dependquestions and this question was skipped.
@@ -972,7 +972,7 @@ public function edit_form(edit_question_form $form, questionnaire $questionnaire
         $this->form_required($mform);
         $this->form_length($mform);
         $this->form_precise($mform);
-        $this->form_question_text($mform, $form->_customdata['modcontext']);
+        $this->form_question_text($mform, ($form->_customdata['modcontext'] ?? ''));
 
         if ($this->has_choices()) {
             // This is used only by the question editing form.
@@ -1228,7 +1228,7 @@ protected function form_extradata(\MoodleQuickForm $mform, $helpname = '') {
      * @param int $value
      * @return \MoodleQuickForm
      */
-    static public function form_length_hidden(\MoodleQuickForm $mform, $value = 0) {
+    public static function form_length_hidden(\MoodleQuickForm $mform, $value = 0) {
         $mform->addElement('hidden', 'length', $value);
         $mform->setType('length', PARAM_INT);
         return $mform;
@@ -1241,7 +1241,7 @@ static public function form_length_hidden(\MoodleQuickForm $mform, $value = 0) {
      * @return \MoodleQuickForm
      * @throws \coding_exception
      */
-    static public function form_length_text(\MoodleQuickForm $mform, $helpname = '', $value = 0) {
+    public static function form_length_text(\MoodleQuickForm $mform, $helpname = '', $value = 0) {
         $mform->addElement('text', 'length', get_string($helpname, 'questionnaire'), ['size' => '1'], $value);
         $mform->setType('length', PARAM_INT);
         if (!empty($helpname)) {
@@ -1255,7 +1255,7 @@ static public function form_length_text(\MoodleQuickForm $mform, $helpname = '',
      * @param int $value
      * @return \MoodleQuickForm
      */
-    static public function form_precise_hidden(\MoodleQuickForm $mform, $value = 0) {
+    public static function form_precise_hidden(\MoodleQuickForm $mform, $value = 0) {
         $mform->addElement('hidden', 'precise', $value);
         $mform->setType('precise', PARAM_INT);
         return $mform;
@@ -1268,7 +1268,7 @@ static public function form_precise_hidden(\MoodleQuickForm $mform, $value = 0)
      * @return \MoodleQuickForm
      * @throws \coding_exception
      */
-    static public function form_precise_text(\MoodleQuickForm $mform, $helpname = '', $value = 0) {
+    public static function form_precise_text(\MoodleQuickForm $mform, $helpname = '', $value = 0) {
         $mform->addElement('text', 'precise', get_string($helpname, 'questionnaire'), ['size' => '1']);
         $mform->setType('precise', PARAM_INT);
         if (!empty($helpname)) {
@@ -1370,7 +1370,7 @@ public function form_update($formdata, $questionnaire) {
             }
 
             while ($nidx < $newcount) {
-                // New choices...
+                // New choices.
                 $choicerecord = new \stdClass();
                 $choicerecord->question_id = $this->qid;
                 $choicerecord->content = trim($newchoices[$nidx]);
diff --git a/classes/question/radio.php b/classes/question/radio.php
index 5c022387..a4c0266d 100644
--- a/classes/question/radio.php
+++ b/classes/question/radio.php
@@ -23,7 +23,6 @@
  */
 
 namespace mod_questionnaire\question;
-use mod_questionnaire\question\choice\choice;
 
 defined('MOODLE_INTERNAL') || die();
 
@@ -84,7 +83,7 @@ public function supports_feedback() {
      *
      */
     protected function question_survey_display($response, $dependants=[], $blankquestionnaire=false) {
-        // Radio buttons
+        // Radio buttons.
         global $idcounter;  // To make sure all radio buttons have unique ids. // JR 20 NOV 2007.
 
         $otherempty = false;
diff --git a/classes/question/rate.php b/classes/question/rate.php
index 57ccee87..1dcbff63 100644
--- a/classes/question/rate.php
+++ b/classes/question/rate.php
@@ -696,12 +696,12 @@ protected function form_extradata(\MoodleQuickForm $mform, $helpname = '') {
      */
     protected function form_preprocess_data($formdata) {
         $nameddegrees = [];
-        // Named degrees are put one per line in the form "[value]=[label]."
+        // Named degrees are put one per line in the form "[value]=[label]".
         if (!empty($formdata->allnameddegrees)) {
             $nameddegreelines = explode("\n", $formdata->allnameddegrees);
             foreach ($nameddegreelines as $nameddegreeline) {
                 $nameddegreeline = trim($nameddegreeline);
-                if (($nameddegree = \mod_questionnaire\question\choice\choice::content_is_named_degree_choice($nameddegreeline)) !==
+                if (($nameddegree = \mod_questionnaire\question\choice::content_is_named_degree_choice($nameddegreeline)) !==
                     false) {
                     $nameddegrees += $nameddegree;
                 }
@@ -762,7 +762,7 @@ protected function form_preprocess_choicedata($formdata) {
      * @throws \dml_exception
      */
     public function update_choice($choicerecord) {
-        if ($nameddegree = choice\choice::content_is_named_degree_choice($choicerecord->content)) {
+        if ($nameddegree = \mod_questionnaire\question\choice::content_is_named_degree_choice($choicerecord->content)) {
             // Preserve any existing value from the new array.
             $this->nameddegrees = $nameddegree + $this->nameddegrees;
             $this->insert_nameddegrees($this->nameddegrees);
@@ -776,7 +776,7 @@ public function update_choice($choicerecord) {
      * @throws \dml_exception
      */
     public function add_choice($choicerecord) {
-        if ($nameddegree = choice\choice::content_is_named_degree_choice($choicerecord->content)) {
+        if ($nameddegree = \mod_questionnaire\question\choice::content_is_named_degree_choice($choicerecord->content)) {
             // Preserve any existing value from the new array.
             $this->nameddegrees = $nameddegree + $this->nameddegrees;
             $this->insert_nameddegrees($this->nameddegrees);
@@ -1001,7 +1001,7 @@ public static function move_nameddegree_choices(int $qid = 0, \stdClass $questio
             if ($question->insert_nameddegrees($nameddegrees)) {
                 // Remove the old named desgree from the choices table.
                 foreach ($oldchoiceids as $choiceid) {
-                    \mod_questionnaire\question\choice\choice::delete_from_db_by_id($choiceid);
+                    \mod_questionnaire\question\choice::delete_from_db_by_id($choiceid);
                 }
 
                 // First get all existing rank responses for this question.
diff --git a/classes/responsetype/boolean.php b/classes/responsetype/boolean.php
index 56c87d4c..04742f43 100644
--- a/classes/responsetype/boolean.php
+++ b/classes/responsetype/boolean.php
@@ -42,7 +42,7 @@ class boolean extends responsetype {
     /**
      * @return string
      */
-    static public function response_table() {
+    public static function response_table() {
         return 'questionnaire_response_bool';
     }
 
@@ -53,7 +53,7 @@ static public function response_table() {
      * @param \mod_questionnaire\question\question $question
      * @return array \mod_questionnaire\responsetype\answer\answer An array of answer objects.
      */
-    static public function answers_from_webform($responsedata, $question) {
+    public static function answers_from_webform($responsedata, $question) {
         $answers = [];
         if (isset($responsedata->{'q'.$question->id}) && !empty($responsedata->{'q'.$question->id})) {
             $record = new \stdClass();
@@ -73,7 +73,7 @@ static public function answers_from_webform($responsedata, $question) {
      * @param \mod_questionnaire\question\question $question
      * @return array \mod_questionnaire\responsetype\answer\answer An array of answer objects.
      */
-    static public function answers_from_appdata($responsedata, $question) {
+    public static function answers_from_appdata($responsedata, $question) {
         if (isset($responsedata->{'q'.$question->id}) && !empty($responsedata->{'q'.$question->id})) {
             $responsedata->{'q'.$question->id} = ($responsedata->{'q'.$question->id}[0] == 1) ? 'y' : 'n';
         }
@@ -238,7 +238,7 @@ public function display_results($rids=false, $sort='', $anonymous=false) {
      * @param int $rid The response id.
      * @return array
      */
-    static public function response_select($rid) {
+    public static function response_select($rid) {
         global $DB;
 
         $values = [];
@@ -273,7 +273,7 @@ static public function response_select($rid) {
      * @return array array answer
      * @throws dml_exception
      */
-    static public function response_answers_by_question($rid) {
+    public static function response_answers_by_question($rid) {
         global $DB;
 
         $answers = [];
diff --git a/classes/responsetype/date.php b/classes/responsetype/date.php
index cf3a990b..9415aee4 100644
--- a/classes/responsetype/date.php
+++ b/classes/responsetype/date.php
@@ -38,7 +38,7 @@ class date extends responsetype {
     /**
      * @return string
      */
-    static public function response_table() {
+    public static function response_table() {
         return 'questionnaire_response_date';
     }
 
@@ -49,7 +49,7 @@ static public function response_table() {
      * @param \mod_questionnaire\question\question $question
      * @return array \mod_questionnaire\responsetype\answer\answer An array of answer objects.
      */
-    static public function answers_from_webform($responsedata, $question) {
+    public static function answers_from_webform($responsedata, $question) {
         $answers = [];
         if (isset($responsedata->{'q'.$question->id}) && !empty($responsedata->{'q'.$question->id})) {
             $record = new \stdClass();
@@ -208,7 +208,7 @@ public function get_results_tags($weights, $participants, $respondents, $showtot
      * @param int $rid The response id.
      * @return array
      */
-    static public function response_select($rid) {
+    public static function response_select($rid) {
         global $DB;
 
         $values = [];
@@ -250,7 +250,7 @@ static public function response_select($rid) {
      * @return array array answer
      * @throws \dml_exception
      */
-    static public function response_answers_by_question($rid) {
+    public static function response_answers_by_question($rid) {
         global $DB;
 
         $answers = [];
diff --git a/classes/responsetype/multiple.php b/classes/responsetype/multiple.php
index 5cc03b9c..3ca8a21a 100644
--- a/classes/responsetype/multiple.php
+++ b/classes/responsetype/multiple.php
@@ -39,7 +39,7 @@ class multiple extends single {
      * The only differences between multuple and single responses are the
      * response table and the insert logic.
      */
-    static public function response_table() {
+    public static function response_table() {
         return 'questionnaire_resp_multiple';
     }
 
@@ -51,7 +51,7 @@ static public function response_table() {
      * @return array \mod_questionnaire\responsetype\answer\answer An array of answer objects.
      * @throws \coding_exception
      */
-    static public function answers_from_webform($responsedata, $question) {
+    public static function answers_from_webform($responsedata, $question) {
         $answers = [];
         if (isset($responsedata->{'q'.$question->id})) {
             foreach ($responsedata->{'q' . $question->id} as $cid => $cvalue) {
@@ -63,7 +63,7 @@ static public function answers_from_webform($responsedata, $question) {
                     $record->choiceid = $cid;
                     // If this choice is an "other" choice, look for the added input.
                     if ($question->choices[$cid]->is_other_choice()) {
-                        $cname = \mod_questionnaire\question\choice\choice::id_other_choice_name($cid);
+                        $cname = \mod_questionnaire\question\choice::id_other_choice_name($cid);
                         $record->value = isset($responsedata->{'q' . $question->id}[$cname]) ?
                             $responsedata->{'q' . $question->id}[$cname] : '';
                     }
@@ -81,7 +81,7 @@ static public function answers_from_webform($responsedata, $question) {
      * @param \mod_questionnaire\question\question $question
      * @return array \mod_questionnaire\responsetype\answer\answer An array of answer objects.
      */
-    static public function answers_from_appdata($responsedata, $question) {
+    public static function answers_from_appdata($responsedata, $question) {
         // Need to override "single" class' implementation.
         $answers = [];
         $qname = 'q'.$question->id;
@@ -94,7 +94,7 @@ static public function answers_from_appdata($responsedata, $question) {
                     $record->choiceid = $choiceid;
                     // If this choice is an "other" choice, look for the added input.
                     if (isset($question->choices[$choiceid]) && $question->choices[$choiceid]->is_other_choice()) {
-                        $cname = \mod_questionnaire\question\choice\choice::id_other_choice_name($choiceid);
+                        $cname = \mod_questionnaire\question\choice::id_other_choice_name($choiceid);
                         $record->value =
                             isset($responsedata->{$qname}[$cname]) ? $responsedata->{$qname}[$cname] : '';
                     } else {
@@ -114,7 +114,7 @@ static public function answers_from_appdata($responsedata, $question) {
      * @param int $rid The response id.
      * @return array
      */
-    static public function response_select($rid) {
+    public static function response_select($rid) {
         global $DB;
 
         $values = [];
@@ -143,8 +143,8 @@ static public function response_select($rid) {
                     $newrow['responses'] = [];
                 }
                 $newrow['responses'][$row->cid] = $row->cid;
-                if (\mod_questionnaire\question\choice\choice::content_is_other_choice($row->ccontent)) {
-                    $newrow['responses'][\mod_questionnaire\question\choice\choice::id_other_choice_name($row->cid)] =
+                if (\mod_questionnaire\question\choice::content_is_other_choice($row->ccontent)) {
+                    $newrow['responses'][\mod_questionnaire\question\choice::id_other_choice_name($row->cid)] =
                         $row->response;
                 }
             }
diff --git a/classes/responsetype/numericaltext.php b/classes/responsetype/numericaltext.php
index 5f3ac154..0f04bb14 100644
--- a/classes/responsetype/numericaltext.php
+++ b/classes/responsetype/numericaltext.php
@@ -42,7 +42,7 @@ class numericaltext extends text {
      * @param \mod_questionnaire\question\question $question
      * @return array \mod_questionnaire\responsetype\answer\answer An array of answer objects.
      */
-    static public function answers_from_webform($responsedata, $question) {
+    public static function answers_from_webform($responsedata, $question) {
         $answers = [];
         if (isset($responsedata->{'q'.$question->id}) && is_numeric($responsedata->{'q'.$question->id})) {
             $val = $responsedata->{'q' . $question->id};
diff --git a/classes/responsetype/rank.php b/classes/responsetype/rank.php
index a4b274cd..2d9d5ffc 100644
--- a/classes/responsetype/rank.php
+++ b/classes/responsetype/rank.php
@@ -39,7 +39,7 @@ class rank extends responsetype {
     /**
      * @return string
      */
-    static public function response_table() {
+    public static function response_table() {
         return 'questionnaire_response_rank';
     }
 
@@ -51,7 +51,7 @@ static public function response_table() {
      * @return array \mod_questionnaire\responsetype\answer\answer An array of answer objects.
      * @throws \coding_exception
      */
-    static public function answers_from_webform($responsedata, $question) {
+    public static function answers_from_webform($responsedata, $question) {
         $answers = [];
         foreach ($question->choices as $cid => $choice) {
             $other = isset($responsedata->{'q' . $question->id . '_' . $cid}) ?
@@ -82,7 +82,7 @@ static public function answers_from_webform($responsedata, $question) {
      * @param \mod_questionnaire\question\question $question
      * @return array \mod_questionnaire\responsetype\answer\answer An array of answer objects.
      */
-    static public function answers_from_appdata($responsedata, $question) {
+    public static function answers_from_appdata($responsedata, $question) {
         $answers = [];
         if (isset($responsedata->{'q'.$question->id}) && !empty($responsedata->{'q'.$question->id})) {
             foreach ($responsedata->{'q' . $question->id} as $choiceid => $choicevalue) {
@@ -344,7 +344,7 @@ public function display_results($rids=false, $sort='', $anonymous=false) {
      * @param int $rid The response id.
      * @return array
      */
-    static public function response_select($rid) {
+    public static function response_select($rid) {
         global $DB;
 
         $values = [];
@@ -411,7 +411,7 @@ static public function response_select($rid) {
      * @return array array answer
      * @throws \dml_exception
      */
-    static public function response_answers_by_question($rid) {
+    public static function response_answers_by_question($rid) {
         global $DB;
 
         $answers = [];
@@ -952,7 +952,7 @@ private function mkrescount($rids, $rows, $sort) {
      * @param $b
      * @return int
      */
-    static private function sortavgasc($a, $b) {
+    private static function sortavgasc($a, $b) {
         if (isset($a->avg) && isset($b->avg)) {
             if ( $a->avg < $b->avg ) {
                 return -1;
@@ -969,7 +969,7 @@ static private function sortavgasc($a, $b) {
      * @param $b
      * @return int
      */
-    static private function sortavgdesc($a, $b) {
+    private static function sortavgdesc($a, $b) {
         if (isset($a->avg) && isset($b->avg)) {
             if ( $a->avg > $b->avg ) {
                 return -1;
diff --git a/classes/responsetype/response/response.php b/classes/responsetype/response/response.php
index 6dcd24e8..bcc25c06 100644
--- a/classes/responsetype/response/response.php
+++ b/classes/responsetype/response/response.php
@@ -108,7 +108,7 @@ public static function create_from_data($responsedata) {
      * @return bool|response A response object.
      * @throws \coding_exception
      */
-    static public function response_from_webform($responsedata, $questions) {
+    public static function response_from_webform($responsedata, $questions) {
         global $USER;
 
         $questionnaireid = isset($responsedata->questionnaire_id) ? $responsedata->questionnaire_id :
@@ -131,7 +131,7 @@ static public function response_from_webform($responsedata, $questions) {
      * @param $questions Array of question objects.
      * @return bool|response A response object.
      */
-    static public function response_from_appdata($questionnaireid, $responseid, $responsedata, $questions) {
+    public static function response_from_appdata($questionnaireid, $responseid, $responsedata, $questions) {
         global $USER;
 
         $response = new response($responseid, $questionnaireid, $USER->id, null, null, null, false);
diff --git a/classes/responsetype/responsetype.php b/classes/responsetype/responsetype.php
index d3543024..a1ce8033 100644
--- a/classes/responsetype/responsetype.php
+++ b/classes/responsetype/responsetype.php
@@ -66,7 +66,7 @@ public function __construct(\mod_questionnaire\question\question $question, int
      *
      * @return string response table name.
      */
-    static public function response_table() {
+    public static function response_table() {
         return 'Must be implemented!';
     }
 
@@ -74,7 +74,7 @@ static public function response_table() {
      * Return the known response tables. Should be replaced by a better management system eventually.
      * @return array
      */
-    static public function all_response_tables() {
+    public static function all_response_tables() {
         return ['questionnaire_response_bool', 'questionnaire_response_date', 'questionnaire_response_other',
             'questionnaire_response_rank', 'questionnaire_response_text', 'questionnaire_resp_multiple',
             'questionnaire_resp_single'];
@@ -87,7 +87,7 @@ static public function all_response_tables() {
      * @param \mod_questionnaire\question\question $question
      * @return array \mod_questionnaire\responsetype\answer\answer An array of answer objects.
      */
-    abstract static public function answers_from_webform($responsedata, $question);
+    abstract public static function answers_from_webform($responsedata, $question);
 
     /**
      * Insert a provided response to the question.
@@ -251,7 +251,7 @@ public function get_feedback_scores(array $rids) {
      * @param int $rid The response id.
      * @return array
      */
-    static public function response_select($rid) {
+    public static function response_select($rid) {
         return [];
     }
 
@@ -262,7 +262,7 @@ static public function response_select($rid) {
      * @param int $rid The response id.
      * @return array array answer
      */
-    static public function response_answers_by_question($rid) {
+    public static function response_answers_by_question($rid) {
         return [];
     }
 
@@ -273,7 +273,7 @@ static public function response_answers_by_question($rid) {
      * @param \mod_questionnaire\question\question $question
      * @return array \mod_questionnaire\responsetype\answer\answer An array of answer objects.
      */
-    static public function answers_from_appdata($responsedata, $question) {
+    public static function answers_from_appdata($responsedata, $question) {
         // In most cases this can be a direct call to answers_from_webform with the one modification below. Override when this will
         // not work.
         if (isset($responsedata->{'q'.$question->id}) && !empty($responsedata->{'q'.$question->id})) {
@@ -289,7 +289,11 @@ static public function answers_from_appdata($responsedata, $question) {
      * @return string
      */
     protected function user_fields_sql() {
-        $userfieldsarr = get_all_user_name_fields();
+        if (class_exists('\core_user\fields')) {
+            $userfieldsarr = \core_user\fields::get_name_fields();
+        } else {
+            $userfieldsarr = get_all_user_name_fields();
+        }
         $userfieldsarr = array_merge($userfieldsarr, ['username', 'department', 'institution']);
         $userfields = '';
         foreach ($userfieldsarr as $field) {
diff --git a/classes/responsetype/single.php b/classes/responsetype/single.php
index 039cd30f..f7a3b67e 100644
--- a/classes/responsetype/single.php
+++ b/classes/responsetype/single.php
@@ -37,7 +37,7 @@ class single extends responsetype {
     /**
      * @return string
      */
-    static public function response_table() {
+    public static function response_table() {
         return 'questionnaire_resp_single';
     }
 
@@ -49,7 +49,7 @@ static public function response_table() {
      * @return array \mod_questionnaire\responsetype\answer\answer An array of answer objects.
      * @throws \coding_exception
      */
-    static public function answers_from_webform($responsedata, $question) {
+    public static function answers_from_webform($responsedata, $question) {
         $answers = [];
         if (isset($responsedata->{'q'.$question->id}) && isset($question->choices[$responsedata->{'q'.$question->id}])) {
             $record = new \stdClass();
@@ -59,7 +59,7 @@ static public function answers_from_webform($responsedata, $question) {
             // If this choice is an "other" choice, look for the added input.
             if ($question->choices[$responsedata->{'q'.$question->id}]->is_other_choice()) {
                 $cname = 'q' . $question->id .
-                    \mod_questionnaire\question\choice\choice::id_other_choice_name($responsedata->{'q'.$question->id});
+                    \mod_questionnaire\question\choice::id_other_choice_name($responsedata->{'q'.$question->id});
                 $record->value = isset($responsedata->{$cname}) ? $responsedata->{$cname} : '';
             }
             $answers[$responsedata->{'q'.$question->id}] = answer\answer::create_from_data($record);
@@ -74,7 +74,7 @@ static public function answers_from_webform($responsedata, $question) {
      * @param \mod_questionnaire\question\question $question
      * @return array \mod_questionnaire\responsetype\answer\answer An array of answer objects.
      */
-    static public function answers_from_appdata($responsedata, $question) {
+    public static function answers_from_appdata($responsedata, $question) {
         $answers = [];
         $qname = 'q'.$question->id;
         if (isset($responsedata->{$qname}[0]) && !empty($responsedata->{$qname}[0])) {
@@ -84,7 +84,7 @@ static public function answers_from_appdata($responsedata, $question) {
             $record->choiceid = $responsedata->{$qname}[0];
             // If this choice is an "other" choice, look for the added input.
             if ($question->choices[$record->choiceid]->is_other_choice()) {
-                $cname = \mod_questionnaire\question\choice\choice::id_other_choice_name($record->choiceid);
+                $cname = \mod_questionnaire\question\choice::id_other_choice_name($record->choiceid);
                 $record->value =
                     isset($responsedata->{$qname}[$cname]) ? $responsedata->{$qname}[$cname] : '';
             } else {
@@ -254,7 +254,7 @@ public function display_results($rids=false, $sort='', $anonymous=false) {
                 if (strpos($idx, 'other') === 0) {
                     $answer = $row->response;
                     $ccontent = $row->content;
-                    $content = \mod_questionnaire\question\choice\choice::content_other_choice_display($ccontent);
+                    $content = \mod_questionnaire\question\choice::content_other_choice_display($ccontent);
                     $content .= ' ' . clean_text($answer);
                     $textidx = $content;
                     $counts[$textidx] = !empty($counts[$textidx]) ? ($counts[$textidx] + 1) : 1;
@@ -278,7 +278,7 @@ public function display_results($rids=false, $sort='', $anonymous=false) {
      * @param int $rid The response id.
      * @return array
      */
-    static public function response_select($rid) {
+    public static function response_select($rid) {
         global $DB;
 
         $values = [];
@@ -294,8 +294,8 @@ static public function response_select($rid) {
             $newrow['ccontent'] = $row->ccontent;
             $newrow['responses'] = [];
             $newrow['responses'][$row->cid] = $row->cid;
-            if (\mod_questionnaire\question\choice\choice::content_is_other_choice($row->ccontent)) {
-                $newrow['responses'][\mod_questionnaire\question\choice\choice::id_other_choice_name($row->cid)] = $row->response;
+            if (\mod_questionnaire\question\choice::content_is_other_choice($row->ccontent)) {
+                $newrow['responses'][\mod_questionnaire\question\choice::id_other_choice_name($row->cid)] = $row->response;
             }
             $values[$row->qid] = $newrow;
         }
@@ -311,7 +311,7 @@ static public function response_select($rid) {
      * @return array array answer
      * @throws \dml_exception
      */
-    static public function response_answers_by_question($rid) {
+    public static function response_answers_by_question($rid) {
         global $DB;
 
         $answers = [];
diff --git a/classes/responsetype/text.php b/classes/responsetype/text.php
index 07cab584..d3ebd9b6 100644
--- a/classes/responsetype/text.php
+++ b/classes/responsetype/text.php
@@ -38,7 +38,7 @@ class text extends responsetype {
     /**
      * @return string
      */
-    static public function response_table() {
+    public static function response_table() {
         return 'questionnaire_response_text';
     }
 
@@ -49,7 +49,7 @@ static public function response_table() {
      * @param \mod_questionnaire\question\question $question
      * @return array \mod_questionnaire\responsetype\answer\answer An array of answer objects.
      */
-    static public function answers_from_webform($responsedata, $question) {
+    public static function answers_from_webform($responsedata, $question) {
         $answers = [];
         if (isset($responsedata->{'q'.$question->id}) && (strlen($responsedata->{'q'.$question->id}) > 0)) {
             $val = $responsedata->{'q' . $question->id};
@@ -271,7 +271,7 @@ public function get_results_tags($weights, $participants, $respondents, $showtot
      * @param int $rid The response id.
      * @return array
      */
-    static public function response_select($rid) {
+    public static function response_select($rid) {
         global $DB;
 
         $values = [];
@@ -304,7 +304,7 @@ static public function response_select($rid) {
      * @return array array answer
      * @throws \dml_exception
      */
-    static public function response_answers_by_question($rid) {
+    public static function response_answers_by_question($rid) {
         global $DB;
 
         $answers = [];
diff --git a/complete.php b/complete.php
index 074ff29c..55448767 100644
--- a/complete.php
+++ b/complete.php
@@ -26,7 +26,7 @@
 $SESSION->questionnaire->current_tab = 'view';
 
 $id = optional_param('id', null, PARAM_INT);    // Course Module ID.
-$a = optional_param('a', null, PARAM_INT);      // questionnaire ID.
+$a = optional_param('a', null, PARAM_INT);      // Questionnaire ID.
 
 $sid = optional_param('sid', null, PARAM_INT);  // Survey id.
 $resume = optional_param('resume', null, PARAM_INT);    // Is this attempt a resume of a saved attempt?
diff --git a/fbsections.php b/fbsections.php
index 71013185..d66f74dc 100644
--- a/fbsections.php
+++ b/fbsections.php
@@ -36,15 +36,15 @@
 $sectionid = optional_param('sectionid', 0, PARAM_INT);
 
 if (! $cm = get_coursemodule_from_id('questionnaire', $id)) {
-    print_error('invalidcoursemodule');
+    throw new \moodle_exception('invalidcoursemodule', 'mod_questionnaire');
 }
 
 if (! $course = $DB->get_record("course", ["id" => $cm->course])) {
-    print_error('coursemisconf');
+    throw new \moodle_exception('coursemisconf', 'mod_questionnaire');
 }
 
 if (! $questionnaire = $DB->get_record("questionnaire", ["id" => $cm->instance])) {
-    print_error('invalidcoursemodule');
+    throw new \moodle_exception('invalidcoursemodule', 'mod_questionnaire');
 }
 
 // Needed here for forced language courses.
@@ -94,7 +94,7 @@
 $SESSION->questionnaire->current_tab = 'feedback';
 
 if (!$questionnaire->capabilities->editquestions) {
-    print_error('nopermissions', 'error', '', 'mod:questionnaire:editquestions');
+    throw new \moodle_exception('nopermissions', 'mod_questionnaire');
 }
 
 // Handle confirmed actions that impact display immediately.
diff --git a/feedback.php b/feedback.php
index dccc0ef5..3644d04a 100644
--- a/feedback.php
+++ b/feedback.php
@@ -33,15 +33,15 @@
 $action = optional_param('action', '', PARAM_ALPHA);
 
 if (! $cm = get_coursemodule_from_id('questionnaire', $id)) {
-    print_error('invalidcoursemodule');
+    throw new \moodle_exception('invalidcoursemodule', 'mod_questionnaire');
 }
 
 if (! $course = $DB->get_record("course", ["id" => $cm->course])) {
-    print_error('coursemisconf');
+    throw new \moodle_exception('coursemisconf', 'mod_questionnaire');
 }
 
 if (! $questionnaire = $DB->get_record("questionnaire", ["id" => $cm->instance])) {
-    print_error('invalidcoursemodule');
+    throw new \moodle_exception('invalidcoursemodule', 'mod_questionnaire');
 }
 
 // Needed here for forced language courses.
@@ -62,7 +62,7 @@
 $SESSION->questionnaire->current_tab = 'feedback';
 
 if (!$questionnaire->capabilities->editquestions) {
-    print_error('nopermissions', 'error', '', 'mod:questionnaire:editquestions');
+    throw new \moodle_exception('nopermissions', 'mod_questionnaire');
 }
 
 $feedbackform = new \mod_questionnaire\feedback_form('feedback.php');
@@ -125,7 +125,7 @@
         }
         $sdata->courseid = $settings->courseid;
         if (!($sid = $questionnaire->survey_update($sdata))) {
-            print_error('couldnotcreatenewsurvey', 'questionnaire');
+            throw new \moodle_exception('couldnotcreatenewsurvey', 'mod_questionnaire');
         }
     }
 
diff --git a/grade.php b/grade.php
index 4ea4a2b7..43780fde 100644
--- a/grade.php
+++ b/grade.php
@@ -31,7 +31,7 @@
 $id = required_param('id', PARAM_INT);
 $cm = get_coursemodule_from_id('questionnaire', $id, 0, false, MUST_EXIST);
 if (! $questionnaire = $DB->get_record("questionnaire", array("id" => $cm->instance))) {
-    print_error('invalidcoursemodule');
+    throw new \moodle_exception('invalidcoursemodule', 'mod_questionnaire');
 }
 $course = $DB->get_record('course', array('id' => $cm->course), '*', MUST_EXIST);
 require_login($course, false, $cm);
diff --git a/index.php b/index.php
index ce65d281..8bddbc75 100644
--- a/index.php
+++ b/index.php
@@ -30,7 +30,7 @@
 $id = required_param('id', PARAM_INT);
 $PAGE->set_url('/mod/questionnaire/index.php', array('id' => $id));
 if (! $course = $DB->get_record('course', array('id' => $id))) {
-    print_error('incorrectcourseid', 'questionnaire');
+    throw new \moodle_exception('Filter has not been set.', 'mod_questionnaire');
 }
 $coursecontext = context_course::instance($id);
 require_login($course->id);
diff --git a/lib.php b/lib.php
index ff0958e2..ddb5d70e 100644
--- a/lib.php
+++ b/lib.php
@@ -99,7 +99,7 @@ function questionnaire_add_instance($questionnaire) {
             $sdata->feedbacknotes = '';
             $sdata->courseid = $course->id;
             if (!($sid = $qobject->survey_update($sdata))) {
-                print_error('couldnotcreatenewsurvey', 'questionnaire');
+                throw new \moodle_exception('couldnotcreatenewsurvey', 'mod_questionnaire');
             }
         } else {
             $copyid = explode('-', $questionnaire->create);
@@ -543,7 +543,7 @@ function questionnaire_extend_settings_navigation(settings_navigation $settings,
     $course = $PAGE->course;
 
     if (! $questionnaire = $DB->get_record("questionnaire", array("id" => $cm->instance))) {
-        print_error('invalidcoursemodule');
+        throw new \moodle_exception('invalidcoursemodule', 'mod_questionnaire');
     }
 
     $courseid = $course->id;
diff --git a/locallib.php b/locallib.php
index 6287a7c6..ea5d6773 100644
--- a/locallib.php
+++ b/locallib.php
@@ -222,7 +222,7 @@ function questionnaire_get_context($cmid) {
     }
 
     if (!$context = context_module::instance($cmid)) {
-            print_error('badcontext');
+        throw new \moodle_exception('badcontext', 'mod_questionnaire');
     }
     return $context;
 }
@@ -854,26 +854,26 @@ function questionnaire_get_standard_page_items($id = null, $a = null) {
 
     if ($id) {
         if (! $cm = get_coursemodule_from_id('questionnaire', $id)) {
-            print_error('invalidcoursemodule');
+            throw new \moodle_exception('invalidcoursemodule', 'mod_questionnaire');
         }
 
         if (! $course = $DB->get_record("course", array("id" => $cm->course))) {
-            print_error('coursemisconf');
+            throw new \moodle_exception('coursemisconf', 'mod_questionnaire');
         }
 
         if (! $questionnaire = $DB->get_record("questionnaire", array("id" => $cm->instance))) {
-            print_error('invalidcoursemodule');
+            throw new \moodle_exception('invalidcoursemodule', 'mod_questionnaire');
         }
 
     } else {
         if (! $questionnaire = $DB->get_record("questionnaire", array("id" => $a))) {
-            print_error('invalidcoursemodule');
+            throw new \moodle_exception('invalidcoursemodule', 'mod_questionnaire');
         }
         if (! $course = $DB->get_record("course", array("id" => $questionnaire->course))) {
-            print_error('coursemisconf');
+            throw new \moodle_exception('coursemisconf', 'mod_questionnaire');
         }
         if (! $cm = get_coursemodule_from_instance("questionnaire", $questionnaire->id, $course->id)) {
-            print_error('invalidcoursemodule');
+            throw new \moodle_exception('invalidcoursemodule', 'mod_questionnaire');
         }
     }
 
diff --git a/myreport.php b/myreport.php
index ad8cd328..c4cf6c33 100644
--- a/myreport.php
+++ b/myreport.php
@@ -27,13 +27,13 @@
 $currentgroupid = optional_param('group', 0, PARAM_INT); // Groupid.
 
 if (! $questionnaire = $DB->get_record("questionnaire", array("id" => $instance))) {
-    print_error('incorrectquestionnaire', 'questionnaire');
+    throw new \moodle_exception('incorrectquestionnaire', 'mod_questionnaire');
 }
 if (! $course = $DB->get_record("course", array("id" => $questionnaire->course))) {
-    print_error('coursemisconf');
+    throw new \moodle_exception('coursemisconf', 'mod_questionnaire');
 }
 if (! $cm = get_coursemodule_from_instance("questionnaire", $questionnaire->id, $course->id)) {
-    print_error('invalidcoursemodule');
+    throw new \moodle_exception('invalidcoursemodule', 'mod_questionnaire');
 }
 
 require_course_login($course, true, $cm);
@@ -42,7 +42,7 @@
 // Should never happen, unless called directly by a snoop...
 if ( !has_capability('mod/questionnaire:readownresponses', $context)
     || $userid != $USER->id) {
-    print_error('Permission denied');
+    throw new \moodle_exception('nopermissions', 'mod_questionnaire');
 }
 $url = new moodle_url($CFG->wwwroot.'/mod/questionnaire/myreport.php', array('instance' => $instance));
 if (isset($userid)) {
@@ -82,7 +82,7 @@
 switch ($action) {
     case 'summary':
         if (empty($questionnaire->survey)) {
-            print_error('surveynotexists', 'questionnaire');
+            throw new \moodle_exception('surveynotexists', 'mod_questionnaire');
         }
         $SESSION->questionnaire->current_tab = 'mysummary';
         $resps = $questionnaire->get_responses($userid);
@@ -110,7 +110,7 @@
 
     case 'vall':
         if (empty($questionnaire->survey)) {
-            print_error('surveynotexists', 'questionnaire');
+            throw new \moodle_exception('surveynotexists', 'mod_questionnaire');
         }
         $SESSION->questionnaire->current_tab = 'myvall';
         $questionnaire->add_user_responses($userid);
@@ -131,7 +131,7 @@
 
     case 'vresp':
         if (empty($questionnaire->survey)) {
-            print_error('surveynotexists', 'questionnaire');
+            throw new \moodle_exception('surveynotexists', 'mod_questionnaire');
         }
         $SESSION->questionnaire->current_tab = 'mybyresponse';
         $usergraph = get_config('questionnaire', 'usergraph');
diff --git a/preview.php b/preview.php
index 7df8eab9..dfdbade6 100644
--- a/preview.php
+++ b/preview.php
@@ -27,22 +27,22 @@
 
 if ($id) {
     if (! $cm = get_coursemodule_from_id('questionnaire', $id)) {
-        print_error('invalidcoursemodule');
+        throw new \moodle_exception('invalidcoursemodule', 'mod_questionnaire');
     }
 
     if (! $course = $DB->get_record("course", array("id" => $cm->course))) {
-        print_error('coursemisconf');
+        throw new \moodle_exception('coursemisconf', 'mod_questionnaire');
     }
 
     if (! $questionnaire = $DB->get_record("questionnaire", array("id" => $cm->instance))) {
-        print_error('invalidcoursemodule');
+        throw new \moodle_exception('invalidcoursemodule', 'mod_questionnaire');
     }
 } else {
     if (! $survey = $DB->get_record("questionnaire_survey", array("id" => $sid))) {
-        print_error('surveynotexists', 'questionnaire');
+        throw new \moodle_exception('surveynotexists', 'mod_questionnaire');
     }
     if (! $course = $DB->get_record("course", ["id" => $survey->courseid])) {
-        print_error('coursemisconf');
+        throw new \moodle_exception('coursemisconf', 'mod_questionnaire');
     }
     // Dummy questionnaire object.
     $questionnaire = new stdClass();
@@ -90,7 +90,7 @@
               (isset($questionnaire->capabilities) && $questionnaire->capabilities->preview);
 if (!$canpreview && !$popup) {
     // Should never happen, unless called directly by a snoop...
-    print_error('nopermissions', 'questionnaire', $CFG->wwwroot.'/mod/questionnaire/view.php?id='.$cm->id);
+    throw new \moodle_exception('nopermissions', 'mod_questionnaire');
 }
 
 if (!isset($SESSION->questionnaire)) {
diff --git a/print.php b/print.php
index d903aba3..b65793c4 100644
--- a/print.php
+++ b/print.php
@@ -25,13 +25,13 @@
 $referer = $CFG->wwwroot.'/mod/questionnaire/report.php';
 
 if (! $questionnaire = $DB->get_record("questionnaire", array("id" => $qid))) {
-    print_error('invalidcoursemodule');
+    throw new \moodle_exception('invalidcoursemodule', 'mod_questionnaire');
 }
 if (! $course = $DB->get_record("course", array("id" => $questionnaire->course))) {
-    print_error('coursemisconf');
+    throw new \moodle_exception('coursemisconf', 'mod_questionnaire');
 }
 if (! $cm = get_coursemodule_from_instance("questionnaire", $questionnaire->id, $course->id)) {
-    print_error('invalidcoursemodule');
+    throw new \moodle_exception('invalidcoursemodule', 'mod_questionnaire');
 }
 
 // Check login and get context.
@@ -50,7 +50,7 @@
 // If you can't view the questionnaire, or can't view a specified response, error out.
 if (!($questionnaire->capabilities->view && (($rid == 0) || $questionnaire->can_view_response($rid)))) {
     // Should never happen, unless called directly by a snoop...
-    print_error('nopermissions', 'moodle', $CFG->wwwroot.'/mod/questionnaire/view.php?id='.$cm->id);
+    throw new \moodle_exception('nopermissions', 'mod_questionnaire');
 }
 $blankquestionnaire = true;
 if ($rid != 0) {
diff --git a/qsettings.php b/qsettings.php
index d767e9a7..30164aec 100644
--- a/qsettings.php
+++ b/qsettings.php
@@ -25,15 +25,15 @@
 $submitbutton2 = optional_param('submitbutton2', '', PARAM_ALPHA);
 
 if (! $cm = get_coursemodule_from_id('questionnaire', $id)) {
-    print_error('invalidcoursemodule');
+    throw new \moodle_exception('invalidcoursemodule', 'mod_questionnaire');
 }
 
 if (! $course = $DB->get_record("course", array("id" => $cm->course))) {
-    print_error('coursemisconf');
+    throw new \moodle_exception('coursemisconf', 'mod_questionnaire');
 }
 
 if (! $questionnaire = $DB->get_record("questionnaire", array("id" => $cm->instance))) {
-    print_error('invalidcoursemodule');
+    throw new \moodle_exception('invalidcoursemodule', 'mod_questionnaire');
 }
 
 // Needed here for forced language courses.
@@ -55,7 +55,7 @@
 $SESSION->questionnaire->current_tab = 'settings';
 
 if (!$questionnaire->capabilities->manage) {
-    print_error('nopermissions', 'error', '', 'mod:questionnaire:manage');
+    throw new \moodle_exception('nopermissions', 'mod_questionnaire');
 }
 
 $settingsform = new \mod_questionnaire\settings_form('qsettings.php');
@@ -106,7 +106,7 @@
 
     $sdata->courseid = $settings->courseid;
     if (!($sid = $questionnaire->survey_update($sdata))) {
-        print_error('couldnotcreatenewsurvey', 'questionnaire');
+        throw new \moodle_exception('couldnotcreatenewsurvey', 'mod_questionnaire');
     } else {
         if ($submitbutton2) {
             $redirecturl = course_get_url($cm->course);
diff --git a/questionnaire.class.php b/questionnaire.class.php
index 90e67c49..5353ca49 100644
--- a/questionnaire.class.php
+++ b/questionnaire.class.php
@@ -1335,7 +1335,14 @@ private function print_survey_start($message, $section, $numsections, $hasrequir
                 if (false) {
                     $linkname = get_string('downloadpdf', 'mod_questionnaire');
                     $link = new moodle_url('/mod/questionnaire/report.php',
-                        ['action' => 'vresp', 'instance' => $this->id, 'target' => 'pdf', 'individualresponse' => 1, 'rid' => $rid]);
+                        [
+                            'action' => 'vresp',
+                            'instance' => $this->id,
+                            'target' => 'pdf',
+                            'individualresponse' => 1,
+                            'rid' => $rid
+                        ]
+                    );
                     $downpdficon = new pix_icon('b/pdfdown', $linkname, 'mod_questionnaire');
                     $respinfo .= $this->renderer->action_link($link, null, null, null, $downpdficon);
                 }
@@ -1425,7 +1432,7 @@ public function survey_print_render($message = '', $referer='', $courseid, $rid=
         global $DB, $CFG;
 
         if (! $course = $DB->get_record("course", array("id" => $courseid))) {
-            print_error('incorrectcourseid', 'questionnaire');
+            throw new \moodle_exception('incorrectcourseid', 'mod_questionnaire');
         }
 
         $this->course = $course;
@@ -1567,7 +1574,7 @@ public function survey_update($sdata) {
             $name = $DB->get_field('questionnaire_survey', 'name', array('id' => $this->survey->id));
 
             // Trying to change survey name.
-            if (trim($name) != trim(stripslashes($sdata->name))) {  // $sdata will already have slashes added to it.
+            if (trim($name) != trim(stripslashes($sdata->name))) {  // Var $sdata will already have slashes added to it.
                 $count = $DB->count_records('questionnaire_survey', array('name' => $sdata->name));
                 if ($count != 0) {
                     $errstr = get_string('errnewname', 'questionnaire');  // TODO: notused!
@@ -2544,6 +2551,7 @@ public function survey_results_navbar_alpha($currrid, $currentgroupid, $cm, $byr
             $respcols = new stdClass();
             for ($i = 0; $i < $colnumber; $i++) {
                 $colname = 'respondentscolumn'.$i;
+                $respcols->$colname = (object)['respondentlink' => []];
                 for ($j = 0; $j < $lines; $j++) {
                     $respcols->{$colname}->respondentlink[] = $resparr[$a];
                     $a++;
@@ -2817,7 +2825,11 @@ protected function choice_types() {
      * @return array|string
      */
     protected function user_fields() {
-        $userfieldsarr = get_all_user_name_fields();
+        if (class_exists('\core_user\fields')) {
+            $userfieldsarr = \core_user\fields::get_name_fields();
+        } else {
+            $userfieldsarr = get_all_user_name_fields();
+        }
         $userfieldsarr = array_merge($userfieldsarr, ['username', 'department', 'institution']);
         return $userfieldsarr;
     }
@@ -3071,7 +3083,7 @@ public function generate_csv($rid='', $userid='', $choicecodes=1, $choicetext=0,
         );
 
         if (!$survey = $DB->get_record('questionnaire_survey', array('id' => $this->survey->id))) {
-            print_error ('surveynotexists', 'questionnaire');
+            throw new \moodle_exception('surveynotexists', 'mod_questionnaire');
         }
 
         // Get all responses for this survey in one go.
@@ -3137,7 +3149,7 @@ public function generate_csv($rid='', $userid='', $choicecodes=1, $choicetext=0,
                         foreach ($choices as $choice) {
                             $content = $choice->content;
                             // If "Other" add a column for the actual "other" text entered.
-                            if (\mod_questionnaire\question\choice\choice::content_is_other_choice($content)) {
+                            if (\mod_questionnaire\question\choice::content_is_other_choice($content)) {
                                 $col = $choice->name.'_'.$stringother;
                                 $columns[][$qpos] = $col;
                                 $questionidcols[][$qpos] = null;
@@ -3165,7 +3177,7 @@ public function generate_csv($rid='', $userid='', $choicecodes=1, $choicetext=0,
                             array_push($types, '0');
                             // If "Other" add a column for the "other" checkbox.
                             // Then add a column for the actual "other" text entered.
-                            if (\mod_questionnaire\question\choice\choice::content_is_other_choice($content)) {
+                            if (\mod_questionnaire\question\choice::content_is_other_choice($content)) {
                                 $content = $stringother;
                                 $col = $choice->name.'->['.$content.']';
                                 $columns[][$qpos] = $col;
@@ -3322,7 +3334,7 @@ public function generate_csv($rid='', $userid='', $choicecodes=1, $choicetext=0,
                     }
                 } else {
                     $content = $choicesbyqid[$qid][$responserow->choice_id]->content;
-                    if (\mod_questionnaire\question\choice\choice::content_is_other_choice($content)) {
+                    if (\mod_questionnaire\question\choice::content_is_other_choice($content)) {
                         // If this is an "other" column, put the text entered in the next position.
                         $row[$position + 1] = $responserow->response;
                         $choicetxt = empty($responserow->choice_id) ? '0' : '1';
@@ -3351,9 +3363,9 @@ public function generate_csv($rid='', $userid='', $choicecodes=1, $choicetext=0,
                     }
 
                     $content = $choicesbyqid[$qid][$responserow->choice_id]->content;
-                    if (\mod_questionnaire\question\choice\choice::content_is_other_choice($content)) {
+                    if (\mod_questionnaire\question\choice::content_is_other_choice($content)) {
                         // If this has an "other" text, use it.
-                        $responsetxt = \mod_questionnaire\question\choice\choice::content_other_choice_display($content);
+                        $responsetxt = \mod_questionnaire\question\choice::content_other_choice_display($content);
                         $responsetxt1 = $responserow->response;
                     } else if (($choicecodes == 1) && ($choicetext == 1)) {
                         $responsetxt = $c.' : '.$content;
@@ -3834,7 +3846,7 @@ public function response_analysis($rid, $resps, $compare, $isgroupmember, $allre
      * @throws moodle_exception
      */
     public function save_mobile_data($userid, $sec, $completed, $rid, $submit, $action, array $responses) {
-        global $DB, $CFG; // Do not delete $CFG!!!
+        global $DB, $CFG; // Do not delete "$CFG".
 
         $ret = [];
         $response = $this->build_response_from_appdata($responses, $sec);
diff --git a/questions.php b/questions.php
index 2f9fa9b2..cab3f550 100644
--- a/questions.php
+++ b/questions.php
@@ -18,24 +18,24 @@
 require_once($CFG->dirroot.'/mod/questionnaire/questionnaire.class.php');
 require_once($CFG->dirroot.'/mod/questionnaire/classes/question/question.php'); // Needed for question type constants.
 
-$id     = required_param('id', PARAM_INT);                 // Course module ID
+$id     = required_param('id', PARAM_INT);                 // Course module ID.
 $action = optional_param('action', 'main', PARAM_ALPHA);   // Screen.
 $qid    = optional_param('qid', 0, PARAM_INT);             // Question id.
 $moveq  = optional_param('moveq', 0, PARAM_INT);           // Question id to move.
-$delq   = optional_param('delq', 0, PARAM_INT);             // Question id to delete
+$delq   = optional_param('delq', 0, PARAM_INT);             // Question id to delete.
 $qtype  = optional_param('type_id', 0, PARAM_INT);         // Question type.
 $currentgroupid = optional_param('group', 0, PARAM_INT); // Group id.
 
 if (! $cm = get_coursemodule_from_id('questionnaire', $id)) {
-    print_error('invalidcoursemodule');
+    throw new \moodle_exception('invalidcoursemodule', 'mod_questionnaire');
 }
 
 if (! $course = $DB->get_record("course", array("id" => $cm->course))) {
-    print_error('coursemisconf');
+    throw new \moodle_exception('coursemisconf', 'mod_questionnaire');
 }
 
 if (! $questionnaire = $DB->get_record("questionnaire", array("id" => $cm->instance))) {
-    print_error('invalidcoursemodule');
+    throw new \moodle_exception('invalidcoursemodule', 'mod_questionnaire');
 }
 
 require_course_login($course, true, $cm);
@@ -57,7 +57,7 @@
 $questionnaire->add_page(new \mod_questionnaire\output\questionspage());
 
 if (!$questionnaire->capabilities->editquestions) {
-    print_error('nopermissions', 'error', '', 'mod:questionnaire:edit');
+    throw new \moodle_exception('nopermissions', 'mod_questionnaire');
 }
 
 $questionnairehasdependencies = $questionnaire->has_dependencies();
diff --git a/report.php b/report.php
index cb413ca0..968d6077 100755
--- a/report.php
+++ b/report.php
@@ -44,20 +44,20 @@
     if (!empty($SESSION->instance)) {
         $instance = $SESSION->instance;
     } else {
-        print_error('requiredparameter', 'questionnaire');
+        throw new \moodle_exception('requiredparameter', 'mod_questionnaire');
     }
 }
 $SESSION->instance = $instance;
 $usergraph = get_config('questionnaire', 'usergraph');
 
 if (! $questionnaire = $DB->get_record("questionnaire", array("id" => $instance))) {
-    print_error('incorrectquestionnaire', 'questionnaire');
+    throw new \moodle_exception('incorrectquestionnaire', 'mod_questionnaire');
 }
 if (! $course = $DB->get_record("course", array("id" => $questionnaire->course))) {
-    print_error('coursemisconf');
+    throw new \moodle_exception('coursemisconf', 'mod_questionnaire');
 }
 if (! $cm = get_coursemodule_from_instance("questionnaire", $questionnaire->id, $course->id)) {
-    print_error('invalidcoursemodule');
+    throw new \moodle_exception('invalidcoursemodule', 'mod_questionnaire');
 }
 
 require_course_login($course, true, $cm);
@@ -80,8 +80,7 @@
 $context = context_module::instance($cm->id);
 if (!$questionnaire->can_view_all_responses()) {
     // Should never happen, unless called directly by a snoop...
-    print_error('nopermissions', 'moodle', $CFG->wwwroot.'/mod/questionnaire/view.php?id='.$cm->id,
-        get_string('viewallresponses', 'mod_questionnaire'));
+    throw new \moodle_exception('nopermissions', 'mod_questionnaire');
 }
 
 $questionnaire->canviewallgroups = has_capability('moodle/site:accessallgroups', $context);
@@ -205,13 +204,13 @@
         if (empty($questionnaire->survey)) {
             $id = $questionnaire->survey;
             notify ("questionnaire->survey = /$id/");
-            print_error('surveynotexists', 'questionnaire');
+            throw new \moodle_exception('surveynotexists', 'mod_questionnaire');
         } else if ($questionnaire->survey->courseid != $course->id) {
-            print_error('surveyowner', 'questionnaire');
+            throw new \moodle_exception('surveyowner', 'mod_questionnaire');
         } else if (!$rid || !is_numeric($rid)) {
-            print_error('invalidresponse', 'questionnaire');
+            throw new \moodle_exception('invalidresponse', 'mod_questionnaire');
         } else if (!($resp = $DB->get_record('questionnaire_response', array('id' => $rid)))) {
-            print_error('invalidresponserecord', 'questionnaire');
+            throw new \moodle_exception('invalidresponserecord', 'mod_questionnaire');
         }
 
         $ruser = false;
@@ -296,13 +295,13 @@
         require_capability('mod/questionnaire:deleteresponses', $context);
 
         if (empty($questionnaire->survey)) {
-            print_error('surveynotexists', 'questionnaire');
+            throw new \moodle_exception('surveynotexists', 'mod_questionnaire');
         } else if ($questionnaire->survey->courseid != $course->id) {
-            print_error('surveyowner', 'questionnaire');
+            throw new \moodle_exception('surveyowner', 'mod_questionnaire');
         } else if (!$rid || !is_numeric($rid)) {
-            print_error('invalidresponse', 'questionnaire');
+            throw new \moodle_exception('invalidresponse', 'mod_questionnaire');
         } else if (!($response = $DB->get_record('questionnaire_response', array('id' => $rid)))) {
-            print_error('invalidresponserecord', 'questionnaire');
+            throw new \moodle_exception('invalidresponserecord', 'mod_questionnaire');
         }
 
         if (questionnaire_delete_response($response, $questionnaire)) {
@@ -344,9 +343,9 @@
         require_capability('mod/questionnaire:deleteresponses', $context);
 
         if (empty($questionnaire->survey)) {
-            print_error('surveynotexists', 'questionnaire');
+            throw new \moodle_exception('surveynotexists', 'mod_questionnaire');
         } else if ($questionnaire->survey->courseid != $course->id) {
-            print_error('surveyowner', 'questionnaire');
+            throw new \moodle_exception('surveyowner', 'mod_questionnaire');
         }
 
         // Available group modes (0 = no groups; 1 = separate groups; 2 = visible groups).
@@ -532,7 +531,7 @@
         if (!$questionnaire->capabilities->readallresponses && !$questionnaire->capabilities->readallresponseanytime) {
             echo $questionnaire->renderer->header();
             // Should never happen, unless called directly by a snoop.
-            print_error('nopermissions', '', '', get_string('viewallresponses', 'questionnaire'));
+            throw new \moodle_exception('nopermissions', 'mod_questionnaire');
             // Finish the page.
             echo $questionnaire->renderer->footer($course);
             break;
@@ -682,9 +681,9 @@
     case 'vresp': // View by response.
     default:
         if (empty($questionnaire->survey)) {
-            print_error('surveynotexists', 'questionnaire');
+            throw new \moodle_exception('surveynotexists', 'mod_questionnaire');
         } else if ($questionnaire->survey->courseid != $course->id) {
-            print_error('surveyowner', 'questionnaire');
+            throw new \moodle_exception('surveyowner', 'mod_questionnaire');
         }
         $ruser = false;
         $noresponses = false;
diff --git a/show_nonrespondents.php b/show_nonrespondents.php
index 33b7e07b..09284847 100644
--- a/show_nonrespondents.php
+++ b/show_nonrespondents.php
@@ -52,25 +52,25 @@
 
 if ($id) {
     if (! $cm = get_coursemodule_from_id('questionnaire', $id)) {
-        print_error('invalidcoursemodule');
+        throw new \moodle_exception('invalidcoursemodule', 'mod_questionnaire');
     }
 
     if (! $course = $DB->get_record("course", array("id" => $cm->course))) {
-        print_error('coursemisconf');
+        throw new \moodle_exception('coursemisconf', 'mod_questionnaire');
     }
 
     if (! $questionnaire = $DB->get_record("questionnaire", array("id" => $cm->instance))) {
-        print_error('invalidcoursemodule');
+        throw new \moodle_exception('invalidcoursemodule', 'mod_questionnaire');
     }
 }
 
 if (!$context = context_module::instance($cm->id)) {
-        print_error('badcontext');
+    throw new \moodle_exception('badcontext', 'mod_questionnaire');
 }
 
 // We need the coursecontext to allow sending of mass mails.
 if (!$coursecontext = context_course::instance($course->id)) {
-        print_error('badcontext');
+    throw new \moodle_exception('badcontext', 'mod_questionnaire');
 }
 
 require_course_login($course, true, $cm);
@@ -89,7 +89,7 @@
 $sid = $questionnaire->sid;
 
 if (($formdata = data_submitted()) && !confirm_sesskey()) {
-    print_error('invalidsesskey');
+    throw new \moodle_exception('invalidsesskey', 'mod_questionnaire');
 }
 
 require_capability('mod/questionnaire:viewsingleresponse', $context);
@@ -203,7 +203,11 @@
     $tablecolumns = array('userpic', 'fullname');
 
     // Extra columns copied from participants view.
-    $extrafields = get_extra_user_fields($context);
+    if (class_exists('\core_user\fields')) {
+        $extrafields = \core_user\fields::get_identity_fields(null, false);
+    } else {
+        $extrafields = get_extra_user_fields($context);
+    }
     $tableheaders = array(get_string('userpic'), get_string('fullnameuser'));
 
     if (in_array('email', $extrafields) || has_capability('moodle/course:viewhiddenuserfields', $context)) {
diff --git a/tests/responsetypes_test.php b/tests/responsetypes_test.php
index 4700f048..fb1c78e0 100644
--- a/tests/responsetypes_test.php
+++ b/tests/responsetypes_test.php
@@ -164,7 +164,7 @@ public function test_create_response_single() {
             }
         }
         $vals = ['q'.$question->id => $val,
-                 'q'.$question->id.\mod_questionnaire\question\choice\choice::id_other_choice_name($val) => 'Forty-four'];
+                 'q'.$question->id. \mod_questionnaire\question\choice::id_other_choice_name($val) => 'Forty-four'];
         $userid = 2;
         $response = $generator->create_question_response($questionnaire, $question, $vals, $userid);
 
@@ -213,7 +213,7 @@ public function test_create_response_multiple() {
                 $val[$cid] = $cid;
             } else if ($choice->content == '!other=Another number') {
                 $val[$cid] = $cid;
-                $val[\mod_questionnaire\question\choice\choice::id_other_choice_name($cid)] = 'Forty-four';
+                $val[\mod_questionnaire\question\choice::id_other_choice_name($cid)] = 'Forty-four';
                 $ocid = $cid;
             }
         }
diff --git a/version.php b/version.php
index 5888f14d..5c52a38b 100644
--- a/version.php
+++ b/version.php
@@ -24,8 +24,8 @@
 
 defined('MOODLE_INTERNAL') || die();
 
-$plugin->version  = 2020111100;  // The current module version (Date: YYYYMMDDXX)
-$plugin->requires = 2019052000; // Moodle version (3.7).
+$plugin->version  = 2020111100;  // The current module version (Date: YYYYMMDDXX).
+$plugin->requires = 2020110900; // Moodle version (3.10).
 
 $plugin->component = 'mod_questionnaire';