diff --git a/classes/conversation.php b/classes/conversation.php
index e6ba055..5f9d172 100644
--- a/classes/conversation.php
+++ b/classes/conversation.php
@@ -153,7 +153,7 @@ public function close() {
             throw new \moodle_exception('cannotclosedraftconversation', 'dialogue');
         }
         // Permission check.
-        $canclose = (($this->_authorid == $USER->id) or has_capability('mod/dialogue:closeany', $context));
+        $canclose = (($this->_authorid == $USER->id) || has_capability('mod/dialogue:closeany', $context));
         if (!$canclose) {
             throw new \moodle_exception('nopermissiontoclose', 'dialogue');
         }
@@ -187,7 +187,7 @@ public function delete() {
             return true;
         }
         // Permission to delete conversation.
-        $candelete = ((has_capability('mod/dialogue:delete', $context) and $USER->id == $this->_authorid) or
+        $candelete = ((has_capability('mod/dialogue:delete', $context) && $USER->id == $this->_authorid) ||
             has_capability('mod/dialogue:deleteany', $context));
 
         if (!$candelete) {
@@ -315,7 +315,7 @@ public function initialise_form() {
         // Set bulk open bulk.
         $bulkopenrule = $this->bulkopenrule; // Insure loaded by using magic.
 
-        if (!empty($bulkopenrule) and has_capability('mod/dialogue:bulkopenrulecreate', $context)) {
+        if (!empty($bulkopenrule) && has_capability('mod/dialogue:bulkopenrulecreate', $context)) {
             // Format for option item e.g. course-1, group-1.
             $groupinformation = $bulkopenrule['type'] . '-' . $bulkopenrule['sourceid'];
             $form->set_data(array('groupinformation' => $groupinformation));
@@ -339,7 +339,7 @@ public function initialise_form() {
         // Set attachments.
         $form->set_data(array('attachments[itemid]' => $this->_attachmentsdraftid));
         // Remove any unecessary buttons.
-        if (($USER->id != $this->author->id) or is_null($this->conversationid)) {
+        if (($USER->id != $this->author->id) || is_null($this->conversationid)) {
             $form->remove_from_group('trash', 'actionbuttongroup');
         }
         // Attach initialised form to conversation class and return.
@@ -470,7 +470,7 @@ public function save() {
         global $DB, $USER;
 
         $admin = get_admin(); // Possible cronjob.
-        if ($USER->id != $admin->id and $USER->id != $this->_authorid) {
+        if ($USER->id != $admin->id && $USER->id != $this->_authorid) {
             throw new \moodle_exception("This conversation doesn't belong to you!");
         }
 
@@ -651,8 +651,8 @@ public function send() {
         $cm      = $this->dialogue->cm;
         $course  = $this->dialogue->course;
 
-        $incomplete = ((empty($this->_bulkopenrule) and empty($this->_participants)) or
-            empty($this->_subject) or empty($this->_body));
+        $incomplete = ((empty($this->_bulkopenrule) && empty($this->_participants)) ||
+            empty($this->_subject) || empty($this->_body));
 
         if ($incomplete) {
             throw new \moodle_exception("incompleteconversation", 'mod_dialogue');
@@ -682,7 +682,7 @@ protected function set_bulk_open_rule($type = null, $sourceid = null, $includefu
         /* Must have type (course, group) and sourceid (course->id, group->id) to
          * be a rule, else is empty.
          */
-        if (!is_null($type) and !is_null($sourceid)) {
+        if (!is_null($type) && !is_null($sourceid)) {
             $rule['type'] = (string) $type;
             $rule['sourceid'] = (int) $sourceid;
             $rule['includefuturemembers'] = (int) $includefuturemembers;
diff --git a/classes/local/course_enrolment_manager.php b/classes/local/course_enrolment_manager.php
index bacd767..0b0898b 100644
--- a/classes/local/course_enrolment_manager.php
+++ b/classes/local/course_enrolment_manager.php
@@ -38,7 +38,7 @@ class course_enrolment_manager extends \course_enrolment_manager {
      *      boolean moreusers True if there are still more users, otherwise is False.
      */
     public function search_users_with_groups(string $search = '', bool $searchanywhere = false, int $page = 0, int $perpage = 25,
-            array $groups) {
+            array $groups = []) {
         global $DB;
 
         [$ufields, $joins, $params, $wherecondition] = $this->get_basic_search_conditions($search, $searchanywhere);
diff --git a/classes/message.php b/classes/message.php
index b89f4fd..7654ac8 100644
--- a/classes/message.php
+++ b/classes/message.php
@@ -133,7 +133,7 @@ public function delete() {
             return true;
         }
         // Permission to delete conversation.
-        $candelete = ((has_capability('mod/dialogue:delete', $context) and $USER->id == $this->_authorid) or
+        $candelete = ((has_capability('mod/dialogue:delete', $context) && $USER->id == $this->_authorid) ||
             has_capability('mod/dialogue:deleteany', $context));
 
         if (!$candelete) {
@@ -326,7 +326,7 @@ public function set_body($body, $format, $itemid = null) {
         $this->_body = $body;
         $this->_bodyformat = $format;
 
-        if ($format == FORMAT_HTML and isset($itemid)) {
+        if ($format == FORMAT_HTML && isset($itemid)) {
             $this->_bodydraftid = $itemid;
             $this->_body = file_rewrite_urls_to_pluginfile($this->_body, $this->_bodydraftid);
         }
@@ -372,7 +372,7 @@ public function save() {
         global $DB, $USER;
 
         $admin = get_admin(); // Possible cronjob.
-        if ($USER->id != $admin->id and $USER->id != $this->_authorid) {
+        if ($USER->id != $admin->id && $USER->id != $this->_authorid) {
             throw new \moodle_exception("This doesn't belong to you!");
         }
 
diff --git a/classes/reply.php b/classes/reply.php
index efb35d0..64ec166 100644
--- a/classes/reply.php
+++ b/classes/reply.php
@@ -125,12 +125,12 @@ public function initialise_form() {
         }
 
         // Remove any unecessary buttons.
-        if (($USER->id != $this->author->id) or is_null($this->messageid)) {
+        if (($USER->id != $this->author->id) || is_null($this->messageid)) {
             $form->remove_from_group('delete', 'actionbuttongroup');
         }
 
         // Remove any unecessary buttons.
-        if (($USER->id != $this->author->id) or is_null($this->messageid)) {
+        if (($USER->id != $this->author->id) || is_null($this->messageid)) {
             $form->remove_from_group('trash', 'actionbuttongroup');
         }
 
@@ -168,7 +168,7 @@ public function send() {
         $conversationid = $this->conversation->conversationid;
 
         // Check permission.
-        if ($USER->id != $this->_authorid or !has_capability('mod/dialogue:reply', $context)) {
+        if ($USER->id != $this->_authorid || !has_capability('mod/dialogue:reply', $context)) {
             throw new \moodle_exception("This doesn't belong to you!");
         }
 
diff --git a/classes/search/activity.php b/classes/search/activity.php
index e971d1d..17c2316 100644
--- a/classes/search/activity.php
+++ b/classes/search/activity.php
@@ -25,8 +25,6 @@
 
 namespace mod_dialogue\search;
 
-defined('MOODLE_INTERNAL') || die();
-
 /**
  * Search area for mod_dialogue activities.
  *
diff --git a/classes/search/conversations.php b/classes/search/conversations.php
index db04ec8..f302798 100644
--- a/classes/search/conversations.php
+++ b/classes/search/conversations.php
@@ -25,8 +25,6 @@
 
 namespace mod_dialogue\search;
 
-defined('MOODLE_INTERNAL') || die();
-
 /**
  * Search area for mod_dialogue conversatoins and messages.
  *
@@ -96,7 +94,7 @@ public function get_document($record, $options = array()) {
         $doc->set('owneruserid', \core_search\manager::NO_OWNER_ID);
         $doc->set('modified', $record->timemodified);
 
-        // // Check if this document should be considered new.
+        // Check if this document should be considered new.
         if (isset($options['lastindexedtime']) && ($options['lastindexedtime'] < $record->timemodified)) {
             // If the document was created after the last index time, it must be new.
             $doc->set_is_new(true);
@@ -157,7 +155,8 @@ public function get_doc_url(\core_search\document $doc) {
     public function get_context_url(\core_search\document $doc) {
         $context = \context::instance_by_id($doc->get('contextid'));
         $entry = $this->get_dialogue_conversations($doc->get('itemid'));
-        return new \moodle_url('/mod/dialogue/conversation.php', array('id' => $context->instanceid, 'action' => 'view', 'conversationid' => $entry->messageid));
+        return new \moodle_url('/mod/dialogue/conversation.php',
+            ['id' => $context->instanceid, 'action' => 'view', 'conversationid' => $entry->messageid]);
     }
 
     /**
@@ -213,4 +212,4 @@ public function attach_files($doc) {
         }
     }
 
-}
\ No newline at end of file
+}
diff --git a/conversation.php b/conversation.php
index 0c90ef9..a540523 100644
--- a/conversation.php
+++ b/conversation.php
@@ -58,7 +58,7 @@
 $dialogue = new \mod_dialogue\dialogue($cm, $course, $activityrecord);
 $conversation = new \mod_dialogue\conversation($dialogue, $conversationid);
 
-if ($action == 'create' or $action == 'edit') {
+if ($action == 'create' || $action == 'edit') {
     require_capability('mod/dialogue:open', $context);
     $form = $conversation->initialise_form();
     if ($form->is_submitted()) {
@@ -156,13 +156,13 @@
 }
 
 if ($conversation->state == \mod_dialogue\dialogue::STATE_BULK_AUTOMATED) {
-    if (!has_capability('mod/dialogue:bulkopenruleeditany', $context) and $conversation->author->id != $USER->id) {
+    if (!has_capability('mod/dialogue:bulkopenruleeditany', $context) && $conversation->author->id != $USER->id) {
         throw new moodle_exception('nopermission');
     }
 }
 
-if ($conversation->state == \mod_dialogue\dialogue::STATE_OPEN or $conversation->state == \mod_dialogue\dialogue::STATE_CLOSED) {
-    if (!has_capability('mod/dialogue:viewany', $context) and !$conversation->is_participant()) {
+if ($conversation->state == \mod_dialogue\dialogue::STATE_OPEN || $conversation->state == \mod_dialogue\dialogue::STATE_CLOSED) {
+    if (!has_capability('mod/dialogue:viewany', $context) && !$conversation->is_participant()) {
         throw new moodle_exception('nopermission');
     }
 }
@@ -181,11 +181,11 @@
 }
 
 // Output reply form if meets criteria.
-$hasreplycapability = (has_capability('mod/dialogue:reply', $context) or
+$hasreplycapability = (has_capability('mod/dialogue:reply', $context) ||
                        has_capability('mod/dialogue:replyany', $context));
 
 // Conversation is open and user can reply... then output reply form.
-if ($hasreplycapability and $conversation->state == \mod_dialogue\dialogue::STATE_OPEN) {
+if ($hasreplycapability && $conversation->state == \mod_dialogue\dialogue::STATE_OPEN) {
     $reply = $conversation->reply();
     $form = $reply->initialise_form();
     $form->display();
diff --git a/formlib.php b/formlib.php
index 73c99d7..8f56cd7 100644
--- a/formlib.php
+++ b/formlib.php
@@ -48,7 +48,7 @@ protected function definition() {
         $mform->setType('body', PARAM_RAW);
 
         // Maxattachments = 0 = No attachments at all.
-        if (!get_config('dialogue', 'maxattachments') or !empty($PAGE->activityrecord->maxattachments)) {
+        if (!get_config('dialogue', 'maxattachments') || !empty($PAGE->activityrecord->maxattachments)) {
             $mform->addElement('filemanager', 'attachments[itemid]',
                 get_string('attachments', 'dialogue'), null, self::attachment_options());
         }
diff --git a/lang/en/dialogue.php b/lang/en/dialogue.php
index 613dc26..d63119d 100644
--- a/lang/en/dialogue.php
+++ b/lang/en/dialogue.php
@@ -183,7 +183,7 @@
 $string['runsuntil'] = 'Runs until ';
 $string['savedraft'] = 'Save draft';
 $string['search:activity'] = 'Dialogue - activity information';
-$string['search:conversations'] =  'Dialogue - conversation and message information';
+$string['search:conversations'] = 'Dialogue - conversation and message information';
 $string['searchpotentials'] = ' Search potentials...';
 $string['second'] = 'second';
 $string['seconds'] = 'seconds';
diff --git a/lib.php b/lib.php
index fade1a5..da97b11 100644
--- a/lib.php
+++ b/lib.php
@@ -402,7 +402,7 @@ function dialogue_can_track_dialogue($user = false) {
     }
 
     // Dont allow guests to track.
-    if (isguestuser($user) or empty($user->id)) {
+    if (isguestuser($user) || empty($user->id)) {
         return false;
     }
 
@@ -451,7 +451,7 @@ function dialogue_pluginfile($course, $cm, $context, $filearea, $args, $forcedow
     $fs = get_file_storage();
     $relativepath = implode('/', $args);
     $fullpath = "/$context->id/mod_dialogue/$filearea/$itemid/$relativepath";
-    if (!$file = $fs->get_file_by_hash(sha1($fullpath)) or $file->is_directory()) {
+    if (!$file = $fs->get_file_by_hash(sha1($fullpath)) || $file->is_directory()) {
         return false;
     }
 
diff --git a/locallib.php b/locallib.php
index 916534e..d4e5579 100644
--- a/locallib.php
+++ b/locallib.php
@@ -207,7 +207,7 @@ function dialogue_cm_unread_total(\mod_dialogue\dialogue $dialogue) {
 
     // Get user's total unread count for a dialogue.
     $record = (array) $DB->get_record_sql($sql, $params);
-    if (isset($record['unread']) and $record['unread'] > 0) {
+    if (isset($record['unread']) && $record['unread'] > 0) {
         return (int) $record['unread'];
     }
     return 0;
@@ -329,7 +329,7 @@ function dialogue_generate_summary_line($subject, $body, $bodyformat, $length =
     $body    = html_to_text($body, 0, false);
 
     $diff = $length - (strlen($subject) + strlen($separator));
-    if (\core_text::strlen($subject) > $length or ! $diff) {
+    if (\core_text::strlen($subject) > $length || ! $diff) {
         return html_writer::tag('strong', shorten_text($subject, $length));
     }
 
diff --git a/renderer.php b/renderer.php
index ef58344..766eaa4 100644
--- a/renderer.php
+++ b/renderer.php
@@ -86,7 +86,7 @@ public function render_conversation(mod_dialogue\conversation $conversation) {
         $html .= html_writer::start_tag('ul', array('class' => "message-actions pull-right"));
 
         if ($conversation->state == \mod_dialogue\dialogue::STATE_OPEN) {
-            $canclose = ((has_capability('mod/dialogue:close', $context) and $USER->id == $conversation->author->id) or
+            $canclose = ((has_capability('mod/dialogue:close', $context) && $USER->id == $conversation->author->id) ||
                           has_capability('mod/dialogue:closeany', $context));
 
             if ($canclose) {
@@ -101,7 +101,7 @@ public function render_conversation(mod_dialogue\conversation $conversation) {
             }
         }
 
-        $candelete = ((has_capability('mod/dialogue:delete', $context) and $USER->id == $conversation->author->id) or
+        $candelete = ((has_capability('mod/dialogue:delete', $context) && $USER->id == $conversation->author->id) ||
                        has_capability('mod/dialogue:deleteany', $context));
 
         if ($candelete) {
@@ -244,7 +244,7 @@ public function conversation_listing(\mod_dialogue\conversations $conversations)
                     $html .= html_writer::tag('td', fullname($displayuser));
                 }
 
-                if (isset($record->subject) and isset($record->body)) {
+                if (isset($record->subject) && isset($record->body)) {
                     $subject = empty($record->subject) ? get_string('nosubject', 'dialogue') : $record->subject;
                     $summaryline = dialogue_generate_summary_line($subject, $record->body, $record->bodyformat);
                     $html .= html_writer::start_tag('td');
@@ -616,7 +616,7 @@ public function tab_navigation(\mod_dialogue\dialogue $dialogue) {
         $html .= html_writer::link($viewurl, get_string('viewconversations', 'dialogue'));
         $html .= html_writer::end_tag('li');
         // Experimental: link conversation by role listing.
-        if (!empty($config->viewconversationsbyrole) and has_capability('mod/dialogue:viewbyrole', $context)) {
+        if (!empty($config->viewconversationsbyrole) && has_capability('mod/dialogue:viewbyrole', $context)) {
             $active = ($currentpage == 'viewconversationsbyrole') ? array('class' => 'active') : array();
             $html .= html_writer::start_tag('li', $active);
             $viewurl = new moodle_url('viewconversationsbyrole.php', array('id' => $cm->id));