diff --git a/public/main/forum/editpost.php b/public/main/forum/editpost.php
index 67ee9c61e2..2fb8349eb5 100644
--- a/public/main/forum/editpost.php
+++ b/public/main/forum/editpost.php
@@ -6,6 +6,7 @@ use Chamilo\CoreBundle\Framework\Container;
 use Chamilo\CourseBundle\Entity\CForum;
 use Chamilo\CourseBundle\Entity\CForumPost;
 use Chamilo\CourseBundle\Entity\CForumThread;
+use Chamilo\CoreBundle\Component\Utils\ActionIcon;
 
 /**
  * These files are a complete rework of the forum. The database structure is
@@ -194,7 +195,7 @@ $htmlHeadXtra[] = <<<JS
                 name: 'user_upload[]'
             });
             $('[name="user_upload[]"]').parent().append(newInputFile);
-        });
+        })
     });
     </script>
 JS;
@@ -248,30 +249,15 @@ if ('learnpath' !== $origin) {
     //$actions .= '<span style="float:right;">'.search_link().'</span>';
     if ('group' === $origin) {
         $actions .= '<a href="../group/group_space.php?'.api_get_cidreq().'">'.
-            Display::return_icon(
-                'back.png',
-                get_lang('Back to').' '.get_lang('Groups'),
-                '',
-                ICON_SIZE_MEDIUM
-            ).
+            Display::getMdiIcon(ActionIcon::BACK, 'ch-tool-icon', null, ICON_SIZE_MEDIUM, get_lang('Back to').' '.get_lang('Groups')).
             '</a>';
     } else {
         $actions .= '<a href="index.php?'.api_get_cidreq().'">'.
-            Display::return_icon(
-                'back.png',
-                get_lang('Back toForumOverview'),
-                '',
-                ICON_SIZE_MEDIUM
-            ).
+            Display::getMdiIcon(ActionIcon::BACK, 'ch-tool-icon', null, ICON_SIZE_MEDIUM, get_lang('Back toForumOverview')).
             '</a>';
     }
     $actions .= '<a href="viewforum.php?forum='.$forumId.'&'.api_get_cidreq().'">'.
-        Display::return_icon(
-            'forum.png',
-            get_lang('Back toForum'),
-            '',
-            ICON_SIZE_MEDIUM
-        ).
+        Display::getMdiIcon('comment-quote', 'ch-tool-icon', null, ICON_SIZE_MEDIUM, get_lang('Back toForum')).
         '</a>';
     echo Display::toolbarAction('toolbar', [$actions]);
 }
diff --git a/public/main/forum/editthread.php b/public/main/forum/editthread.php
index 53ef5d7080..7167a1d56b 100644
--- a/public/main/forum/editthread.php
+++ b/public/main/forum/editthread.php
@@ -4,6 +4,8 @@
 
 use Chamilo\CoreBundle\Framework\Container;
 use Chamilo\CourseBundle\Entity\CForum;
+use Chamilo\CoreBundle\Component\Utils\ActionIcon;
+
 
 /**
  * Edit a Forum Thread.
@@ -200,7 +202,7 @@ $htmlHeadXtra[] = <<<JS
                 $("[name='weight_calification']").val(0);
                 $("[name='thread_peer_qualify'][value='0']").prop('checked', true);
             }
-        });
+        })
     });
     </script>
 JS;
@@ -208,7 +210,7 @@ JS;
 // Action links
 $actions = [
     Display::url(
-        Display::return_icon('back.png', get_lang('Back to forum'), '', ICON_SIZE_MEDIUM),
+        Display::getMdiIcon(ActionIcon::BACK, 'ch-tool-icon', null, ICON_SIZE_MEDIUM, get_lang('Back to forum')),
         'viewforum.php?forum='.$forumId.'&'.$cidreq
     ),
     search_link(),
diff --git a/public/main/forum/forumfunction.inc.php b/public/main/forum/forumfunction.inc.php
index 99f5f2a2b8..bb62b7ed38 100644
--- a/public/main/forum/forumfunction.inc.php
+++ b/public/main/forum/forumfunction.inc.php
@@ -19,6 +19,8 @@ use Chamilo\CourseBundle\Entity\CLpItem;
 use ChamiloSession as Session;
 use Doctrine\Common\Collections\Criteria;
 use Symfony\Component\HttpFoundation\File\UploadedFile;
+use Chamilo\CoreBundle\Component\Utils\ActionIcon;
+
 
 /**
  * @todo convert this library into a class
@@ -918,7 +920,7 @@ function returnVisibleInvisibleIcon(
             }
         }
         $html .= 'action=invisible&content='.$content.'&id='.$id.'">'.
-            Display::return_icon('visible.png', get_lang('MakeInvisible'), [], ICON_SIZE_SMALL).'</a>';
+            Display::getMdiIcon(ActionIcon::VISIBLE, 'ch-tool-icon', null, ICON_SIZE_SMALL, get_lang('MakeInvisible')).'</a>';
     }
     if (0 == $current_visibility_status) {
         $html .= '<a href="'.api_get_self().'?'.api_get_cidreq().'&';
@@ -928,7 +930,7 @@ function returnVisibleInvisibleIcon(
             }
         }
         $html .= 'action=visible&content='.$content.'&id='.$id.'">'.
-            Display::return_icon('invisible.png', get_lang('Make Visible'), [], ICON_SIZE_SMALL).'</a>';
+            Display::getMdiIcon(ActionIcon::INVISIBLE, 'ch-tool-icon', null, ICON_SIZE_SMALL, get_lang('Make Visible')).'</a>';
     }
 
     return $html;
@@ -952,13 +954,14 @@ function returnLockUnlockIcon(
     //check if the forum is blocked due
     if ('thread' === $content) {
         if (api_resource_is_locked_by_gradebook($id, LINK_FORUM_THREAD)) {
-            return $html.Display::return_icon(
-                    'lock_na.png',
+            return $html.Display::getMdiIcon(
+                    ActionIcon::LOCK,
+                    'ch-tool-icon-disabled',
+                    '',
+                    ICON_SIZE_SMALL,
                     get_lang(
                         'This option is not available because this activity is contained by an assessment, which is currently locked. To unlock the assessment, ask your platform administrator.'
-                    ),
-                    [],
-                    ICON_SIZE_SMALL
+                    )
                 );
         }
     }
@@ -970,7 +973,7 @@ function returnLockUnlockIcon(
             }
         }
         $html .= 'action=unlock&content='.$content.'&id='.$id.'">'.
-            Display::return_icon('lock.png', get_lang('Unlock'), [], ICON_SIZE_SMALL).'</a>';
+            Display::getMdiIcon(ActionIcon::LOCK, 'ch-tool-icon', null, ICON_SIZE_SMALL, get_lang('Unlock')).'</a>';
     }
     if ('0' == $current_lock_status) {
         $html .= '<a href="'.api_get_self().'?'.api_get_cidreq().'&';
@@ -980,7 +983,7 @@ function returnLockUnlockIcon(
             }
         }
         $html .= 'action=lock&content='.$content.'&id='.$id.'">'.
-            Display::return_icon('unlock.png', get_lang('Lock'), [], ICON_SIZE_SMALL).'</a>';
+            Display::getMdiIcon(ActionIcon::UNLOCK, 'ch-tool-icon', null, ICON_SIZE_SMALL, get_lang('Lock')).'</a>';
     }
 
     return $html;
@@ -1017,10 +1020,10 @@ function returnUpDownIcon(string $content, int $id, array $list): string
         $return_value = '<a
                 href="'.api_get_self().'?'.api_get_cidreq().'&action=move&direction=up&content='.$content.'&forumcategory='.$forumCategory.'&id='.$id.'"
                 title="'.get_lang('Move up').'">'.
-            Display::return_icon('up.png', get_lang('Move up'), [], ICON_SIZE_SMALL).'</a>';
+            Display::getMdiIcon(ActionIcon::UP, 'ch-tool-icon', null, ICON_SIZE_SMALL, get_lang('Move up')).'</a>';
     } else {
         $return_value = Display::url(
-            Display::return_icon('up_na.png', '-', [], ICON_SIZE_SMALL),
+            Display::getMdiIcon(ActionIcon::UP, 'ch-tool-icon-disabled', null, ICON_SIZE_SMALL, ''),
             'javascript:void(0)'
         );
     }
@@ -1029,10 +1032,10 @@ function returnUpDownIcon(string $content, int $id, array $list): string
         $return_value .= '<a
             href="'.api_get_self().'?'.api_get_cidreq().'&action=move&direction=down&content='.$content.'&forumcategory='.$forumCategory.'&id='.$id.'"
             title="'.get_lang('Move down').'" >'.
-            Display::return_icon('down.png', get_lang('Move down'), [], ICON_SIZE_SMALL).'</a>';
+            Display::getMdiIcon(ActionIcon::DOWN, 'ch-tool-icon', null, ICON_SIZE_SMALL, get_lang('Move down')).'</a>';
     } else {
         $return_value = Display::url(
-            Display::return_icon('down_na.png', '-', [], ICON_SIZE_SMALL),
+            Display::getMdiIcon(ActionIcon::DOWN, 'ch-tool-icon-disabled', null, ICON_SIZE_SMALL, ''),
             'javascript:void(0)'
         );
     }
@@ -1483,7 +1486,6 @@ function get_thread_users_details(int $thread_id)
                     AND course_user.relation_type <> ".COURSE_RELATION_TYPE_RRHH."
                     AND p.thread_id = $thread_id
                     AND course_user.status != '1' AND
-                    p.c_id = $course_id AND
                     course_user.c_id = $course_id $orderby";
     }
 
@@ -3381,7 +3383,6 @@ function handle_mail_cue($content, $id)
         $sql = "SELECT users.firstname, users.lastname, users.id as user_id, users.email, posts.forum_id
                 FROM $table_mailcue mailcue, $table_posts posts, $table_users users
                 WHERE
-                    posts.c_id = $course_id AND
                     mailcue.c_id = $course_id AND
                     posts.thread_id = $id AND
                     posts.post_notification = '1' AND
@@ -4000,7 +4001,7 @@ function search_link()
     $origin = api_get_origin();
     if ('learnpath' != $origin) {
         $return = '<a href="forumsearch.php?'.api_get_cidreq().'&action=search"> ';
-        $return .= Display::return_icon('search.png', get_lang('Search'), '', ICON_SIZE_MEDIUM).'</a>';
+        $return .= Display::getMdiIcon('magnify-plus-outline	', 'ch-tool-icon', null, ICON_SIZE_SMALL, get_lang('Search')).'</a>';
 
         if (!empty($_GET['search'])) {
             $return .= ': '.Security::remove_XSS($_GET['search']).' ';
@@ -4012,7 +4013,7 @@ function search_link()
                 }
             }
             $url .= implode('&', $url_parameter);
-            $return .= '<a href="'.$url.'">'.Display::return_icon('delete.gif', get_lang('Clean search results')).'</a>';
+            $return .= '<a href="'.$url.'">'.Display::getMdiIcon(ActionIcon::DELETE, 'ch-tool-icon', '', ICON_SIZE_SMALL,  get_lang('Clean search results')).'</a>';
         }
     }
 
@@ -4638,20 +4639,20 @@ function get_thread_user_post(Course $course, $thread_id, $user_id)
 /**
  * This function get the name of an thread by id.
  *
- * @param int $thread_id
+ * @param int $threadId
  *
  * @return string
  *
  * @author Christian Fasanando
  * @author Julio Montoya <gugli100@gmail.com> Adding security
  */
-function get_name_thread_by_id($thread_id)
+function get_name_thread_by_id(int $threadId): string
 {
-    $t_forum_thread = Database::get_course_table(TABLE_FORUM_THREAD);
+    $tForumThread = Database::get_course_table(TABLE_FORUM_THREAD);
     $course_id = api_get_course_int_id();
     $sql = "SELECT thread_title
-            FROM $t_forum_thread
-            WHERE c_id = $course_id AND iid = '".(int) $thread_id."' ";
+            FROM $tForumThread
+            WHERE iid = $threadId";
     $result = Database::query($sql);
     $row = Database::fetch_array($result);
 
@@ -4700,12 +4701,7 @@ function get_all_post_from_user(int $user_id, int $courseId): string
                         $post_counter = count($post_list);
                         if (is_array($post_list) && count($post_list) > 0) {
                             $hand_forums .= '<div id="social-thread">';
-                            $hand_forums .= Display::return_icon(
-                                'thread.png',
-                                get_lang('Thread'),
-                                '',
-                                ICON_SIZE_MEDIUM
-                            );
+                            $hand_forums .= Display::getMdiIcon('format-quote-open', 'ch-tool-icon', null, ICON_SIZE_SMALL, get_lang('Thread'));
                             $hand_forums .= '&nbsp;'.Security::remove_XSS($thread->getThreadTitle(), STUDENT);
                             $hand_forums .= '</div>';
 
@@ -4724,7 +4720,7 @@ function get_all_post_from_user(int $user_id, int $courseId): string
                 $forum_results .= '<div id="social-forum">';
                 $forum_results .= '<div class="clear"></div><br />';
                 $forum_results .= '<div id="social-forum-title">'.
-                    Display::return_icon('forum.gif', get_lang('Forum')).'&nbsp;'.Security::remove_XSS($forum->getForumTitle(), STUDENT).
+                    Display::getMdiIcon('comment-quote', 'ch-tool-icon', '', ICON_SIZE_SMALL, get_lang('Forum')).'&nbsp;'.Security::remove_XSS($forum->getForumTitle(), STUDENT).
                     '<div style="float:right;margin-top:-35px">
                         <a href="../forum/viewforum.php?'.api_get_cidreq_params($courseId).'&forum='.$forum->getIid().' " >'.
                     get_lang('See forum').'
@@ -5061,16 +5057,16 @@ function getAttachedFiles(
             // Check if $row is consistent
             if ($attachment) {
                 // Set result as success and bring delete URL
-                $json['result'] = Display::return_icon('accept.png', get_lang('Uploaded.'));
+                $json['result'] = Display::getMdiIcon('check-circle', 'ch-tool-icon', null, ICON_SIZE_SMALL, get_lang('Uploaded.'));
                 $url = api_get_path(WEB_CODE_PATH).'forum/viewthread.php?'.api_get_cidreq().'&action=delete_attach&forum='.$forumId.'&thread='.$threadId.'&id_attach='.$row['iid'];
                 $json['delete'] = Display::url(
-                    Display::return_icon('delete.png', get_lang('Delete'), [], ICON_SIZE_SMALL),
+                    Display::getMdiIcon(ActionIcon::DELETE, 'ch-tool-icon', null, ICON_SIZE_SMALL, get_lang('Delete')),
                     $url,
                     ['class' => 'deleteLink']
                 );
             } else {
                 // If not, set an exclamation result
-                $json['result'] = Display::return_icon('exclamation.png', get_lang('Error'));
+                $json['result'] = Display::getMdiIcon('close-circle', 'ch-tool-icon', null, ICON_SIZE_SMALL, get_lang('Error'));
             }
             // Store array data into $_SESSION
             $_SESSION['forum']['upload_file'][$courseId][$json['id']] = $json;
diff --git a/public/main/forum/forumqualify.php b/public/main/forum/forumqualify.php
index 476e238fa5..189613706e 100644
--- a/public/main/forum/forumqualify.php
+++ b/public/main/forum/forumqualify.php
@@ -5,6 +5,8 @@
 use Chamilo\CoreBundle\Framework\Container;
 use Chamilo\CourseBundle\Entity\CForum;
 use Chamilo\CourseBundle\Entity\CForumThread;
+use Chamilo\CoreBundle\Component\Utils\ActionIcon;
+
 
 /**
  * @todo fix all this qualify files avoid including files, use classes POO jmontoya
@@ -339,7 +341,7 @@ if (isset($rows)) {
             echo '<tr ><td height="50%">';
             $realname = $attachment_list['path'];
             $user_filename = $attachment_list['filename'];
-            echo Display::return_icon('attachment.gif', get_lang('Attachment'));
+            echo Display::getMdiIcon('paperclip', 'ch-tool-icon', '', ICON_SIZE_SMALL, get_lang('Attachment'));
             echo '<a href="download.php?file=';
             echo $realname;
             echo ' "> '.$user_filename.' </a>';
diff --git a/public/main/forum/index.php b/public/main/forum/index.php
index 9e74fa4b4c..1361308478 100644
--- a/public/main/forum/index.php
+++ b/public/main/forum/index.php
@@ -4,6 +4,7 @@
 
 use Chamilo\CourseBundle\Entity\CForumPost;
 use ChamiloSession as Session;
+use Chamilo\CoreBundle\Component\Utils\ActionIcon;
 
 /**
  * These files are a complete rework of the forum. The database structure is
@@ -204,11 +205,12 @@ if (!empty($_GET['lp_id']) || !empty($_POST['lp_id'])) {
     $url = '../lp/lp_controller.php?'.api_get_cidreq()
         ."&gradebook=&action=add_item&type=step&lp_id='.$lp_id.'#resource_tab-5";
     $actionLeft .= Display::url(
-        Display::return_icon(
-            'back.png',
-            get_lang('Back to').' '.get_lang('Learning paths'),
+        Display::getMdiIcon(
+            ActionIcon::BACK,
+            'ch-tool-icon',
             null,
-            ICON_SIZE_MEDIUM
+            ICON_SIZE_MEDIUM,
+            get_lang('Back to').' '.get_lang('Learning paths')
         ),
         $url
     );
@@ -217,23 +219,13 @@ if (!empty($_GET['lp_id']) || !empty($_POST['lp_id'])) {
 if (api_is_allowed_to_edit(false, true)) {
     if (is_array($forumCategories) && !empty($forumCategories)) {
         $actionLeft .= Display::url(
-            Display::return_icon(
-                'new_forum.png',
-                get_lang('Add a forum'),
-                null,
-                ICON_SIZE_MEDIUM
-            ),
+            Display::getMdiIcon('comment-quote', 'ch-tool-icon', null, ICON_SIZE_MEDIUM, get_lang('Add a forum')),
             api_get_self().'?'.api_get_cidreq().'&action=add_forum&lp_id='.$lp_id
         );
     }
 
     $actionLeft .= Display::url(
-        Display::return_icon(
-            'new_folder.png',
-            get_lang('Add a forumCategory'),
-            null,
-            ICON_SIZE_MEDIUM
-        ),
+        Display::getMdiIcon('folder-multiple-plus', 'ch-tool-icon', null, ICON_SIZE_MEDIUM, get_lang('Add a forumCategory')),
         api_get_self().'?'.api_get_cidreq().'&action=add_category&lp_id='.$lp_id
     );
 }
@@ -346,12 +338,7 @@ if (is_array($forumCategories)) {
             ) {
                 $tools .= '<a href="'.api_get_self().'?'.api_get_cidreq()
                     .'&action=edit_category&content=forumcategory&id='.$categoryId
-                    .'">'.Display::return_icon(
-                        'edit.png',
-                        get_lang('Edit'),
-                        [],
-                        ICON_SIZE_SMALL
-                    )
+                    .'">'.Display::getMdiIcon(ActionIcon::EDIT, 'ch-tool-icon', null, ICON_SIZE_SMALL, get_lang('Edit'))
                     .'</a>';
 
                 $tools .= '<a href="'.api_get_self().'?'.api_get_cidreq()
@@ -362,12 +349,7 @@ if (is_array($forumCategories)) {
                         ENT_QUOTES
                     ))
                     ."')) return false;\">"
-                    .Display::return_icon(
-                        'delete.png',
-                        get_lang('Delete'),
-                        [],
-                        ICON_SIZE_SMALL
-                    )
+                    .Display::getMdiIcon(ActionIcon::DELETE, 'ch-tool-icon', null, ICON_SIZE_SMALL, get_lang('Delete'))
                     .'</a>';
                 $tools .= returnVisibleInvisibleIcon(
                     'forumcategory',
@@ -542,7 +524,7 @@ if (is_array($forumCategories)) {
                         if (api_is_allowed_to_edit(false, true)) {
                             $toolActions .= '<a href="'.api_get_self().'?'.api_get_cidreq()
                                 .'&action=edit_forum&content=forum&id='.$forumId.'">'
-                                .Display::return_icon('edit.png', get_lang('Edit'), [], ICON_SIZE_SMALL)
+                                .Display::getMdiIcon(ActionIcon::EDIT, 'ch-tool-icon', null, ICON_SIZE_SMALL, get_lang('Edit'))
                                 .'</a>';
                             $toolActions .= '<a href="'.api_get_self().'?'.api_get_cidreq()
                                 .'&action=delete_forum&content=forum&id='.$forumId
@@ -550,7 +532,7 @@ if (is_array($forumCategories)) {
                                     api_htmlentities(get_lang('Delete forum ?'), ENT_QUOTES)
                                 )
                                 ."')) return false;\">"
-                                .Display::return_icon('delete.png', get_lang('Delete'), [], ICON_SIZE_SMALL)
+                                .Display::getMdiIcon(ActionIcon::DELETE, 'ch-tool-icon', null, ICON_SIZE_SMALL, get_lang('Delete'))
                                 .'</a>';
 
                             $toolActions .= returnVisibleInvisibleIcon(
diff --git a/public/main/forum/newthread.php b/public/main/forum/newthread.php
index 6f39fad81a..14a4494e79 100644
--- a/public/main/forum/newthread.php
+++ b/public/main/forum/newthread.php
@@ -4,6 +4,7 @@
 
 use Chamilo\CoreBundle\Framework\Container;
 use Chamilo\CourseBundle\Entity\CForum;
+use Chamilo\CoreBundle\Component\Utils\ActionIcon;
 
 /**
  * These files are a complete rework of the forum. The database structure is
@@ -223,7 +224,7 @@ Display::display_header();
 
 //$actions  '<span style="float:right;">'.search_link().'</span>';
 $actions = '<a href="viewforum.php?forum='.(int) ($_GET['forum']).'&'.$cidreq.'">'.
-    Display::return_icon('back.png', get_lang('Back to forum'), '', ICON_SIZE_MEDIUM).'</a>';
+    Display::getMdiIcon(ActionIcon::BACK, 'ch-tool-icon', null, ICON_SIZE_MEDIUM, get_lang('Back to forum')).'</a>';
 echo Display::toolbarAction('toolbar', [$actions]);
 
 // Set forum attachment data into $_SESSION
diff --git a/public/main/forum/reply.php b/public/main/forum/reply.php
index f70ed188f1..502a76318b 100644
--- a/public/main/forum/reply.php
+++ b/public/main/forum/reply.php
@@ -5,6 +5,7 @@
 use Chamilo\CoreBundle\Framework\Container;
 use Chamilo\CourseBundle\Entity\CForum;
 use Chamilo\CourseBundle\Entity\CForumThread;
+use Chamilo\CoreBundle\Component\Utils\ActionIcon;
 
 /**
  * These files are a complete rework of the forum. The database structure is
@@ -204,7 +205,7 @@ $htmlHeadXtra[] = <<<JS
             });
 
             $('[name="user_upload[]"]').parent().append(newInputFile);
-        });
+        })
     });
     </script>
 JS;
@@ -239,12 +240,7 @@ Display::display_header();
 if ('learnpath' !== $origin) {
     //$actionsLeft = '<span style="float:right;">'.search_link().'</span>';
     $actionsLeft = '<a href="viewthread.php?'.api_get_cidreq().'&forum='.$forumId.'&thread='.$threadId.'">';
-    $actionsLeft .= Display::return_icon(
-        'back.png',
-        get_lang('Back to thread'),
-        '',
-        ICON_SIZE_MEDIUM
-    ).'</a>';
+    $actionsLeft .= Display::getMdiIcon(ActionIcon::BACK, 'ch-tool-icon', null, ICON_SIZE_MEDIUM, get_lang('Back to thread')).'</a>';
 
     echo Display::toolbarAction('toolbar', [$actionsLeft]);
 }
diff --git a/public/main/forum/viewforum.php b/public/main/forum/viewforum.php
index cee02ee991..177f7c668c 100644
--- a/public/main/forum/viewforum.php
+++ b/public/main/forum/viewforum.php
@@ -5,6 +5,8 @@
 use Chamilo\CoreBundle\Framework\Container;
 use Chamilo\CourseBundle\Entity\CForum;
 use Chamilo\CourseBundle\Entity\CForumPost;
+use Chamilo\CoreBundle\Component\Utils\ActionIcon;
+use Chamilo\CoreBundle\Component\Utils\ToolIcon;
 
 require_once __DIR__.'/../inc/global.inc.php';
 
@@ -240,7 +242,7 @@ if ('liststd' === $my_action &&
         $qualificationBlock .= '</tr>';
         $max_qualify = showQualify('2', $userId, $_GET['id']);
         $counter = 0;
-        $icon = Display::return_icon('quiz.png', get_lang('Grade activity'));
+        $icon = Display::getMdiIcon(ActionIcon::GRADE, 'ch-tool-icon', null, ICON_SIZE_SMALL, get_lang('Grade activity'));
         if (Database::num_rows($student_list) > 0) {
             while ($row_student_list = Database::fetch_array($student_list)) {
                 $userInfo = api_get_user_info($row_student_list['id']);
@@ -290,12 +292,12 @@ $actions = '';
 if ('learnpath' !== $origin) {
     if (!empty($groupId)) {
         $actions .= '<a href="'.api_get_path(WEB_CODE_PATH).'group/group_space.php?'.api_get_cidreq().'">'
-            .Display::return_icon('back.png', get_lang('Back to')
+            .Display::getMdiIcon(ActionIcon::BACK, 'ch-tool-icon', null, ICON_SIZE_SMALL, get_lang('Back to')
             .' '.get_lang('Groups'), '', ICON_SIZE_MEDIUM).'</a>';
     } else {
         $actions .= '<span style="float:right;">'.search_link().'</span>';
         $actions .= '<a href="'.$forumUrl.'index.php?'.api_get_cidreq().'">'
-            .Display::return_icon('back.png', get_lang('Back toForumOverview'), '', ICON_SIZE_MEDIUM)
+            .Display::getMdiIcon(ActionIcon::BACK, 'ch-tool-icon', null, ICON_SIZE_MEDIUM, get_lang('Back toForumOverview'))
             .'</a>';
     }
 }
@@ -312,7 +314,7 @@ if (api_is_allowed_to_edit(false, true) ||
         if (!api_is_anonymous() && !api_is_invitee()) {
             $actions .= '<a href="'.$forumUrl.'newthread.php?'.api_get_cidreq().'&forum='
                 .$forumId.'">'
-                .Display::return_icon('new_thread.png', get_lang('Create thread'), '', ICON_SIZE_MEDIUM)
+                .Display::getMdiIcon('format-quote-open', 'ch-tool-icon', null, ICON_SIZE_MEDIUM, get_lang('Create thread'))
                 .'</a>';
         }
     } else {
@@ -321,12 +323,7 @@ if (api_is_allowed_to_edit(false, true) ||
 }
 
 $descriptionForum = $forumEntity->getForumComment();
-$iconForum = Display::return_icon(
-    'forum_yellow.png',
-    get_lang('Forum'),
-    null,
-    ICON_SIZE_MEDIUM
-);
+$iconForum = Display::getMdiIcon('comment-quote', 'ch-tool-icon', null, ICON_SIZE_MEDIUM, get_lang('Forum'));
 
 $header = '';
 // The current forum
@@ -426,14 +423,9 @@ if (is_array($threads)) {
             }
 
             $html .= '<div class="col-md-4">'
-                .Display::return_icon('post-forum.png', null, null, ICON_SIZE_SMALL)
+                .Display::getMdiIcon('format-quote-open', 'ch-tool-icon', '', ICON_SIZE_SMALL, get_lang('Replies'))
                 ." {$thread->getThreadReplies()} ".get_lang('Replies').'<br>';
-            $html .= Display::return_icon(
-                'post-forum.png',
-                null,
-                null,
-                ICON_SIZE_SMALL
-            ).' '.$thread->getThreadReplies().' '.get_lang('Views').'<br>';
+            $html .= Display::getMdiIcon('format-quote-open', 'ch-tool-icon', '', ICON_SIZE_SMALL, get_lang('Views')).' '.$thread->getThreadReplies().' '.get_lang('Views').'<br>';
             $html .= '</div>';
             $last_post = null;
             if ($thread->getThreadLastPost()) {
@@ -457,20 +449,15 @@ if (is_array($threads)) {
                         .'&forum='.$forumId.'&thread='
                         .$thread->getIid()
                         .'&id_attach='.$id_attach.'">'
-                        .Display::return_icon('edit.png', get_lang('Edit'), [], ICON_SIZE_SMALL).'</a>';
+                        .Display::getMdiIcon(ActionIcon::EDIT, 'ch-tool-icon', null, ICON_SIZE_SMALL, get_lang('Edit')).'</a>';
                     if (api_resource_is_locked_by_gradebook($thread->getIid(), LINK_FORUM_THREAD)) {
-                        $iconsEdit .= Display::return_icon(
-                            'delete_na.png',
-                            get_lang('This option is not available because this activity is contained by an assessment, which is currently locked. To unlock the assessment, ask your platform administrator.'),
-                            [],
-                            ICON_SIZE_SMALL
-                        );
+                        $iconsEdit .= Display::getMdiIcon(ActionIcon::DELETE, 'ch-tool-icon-disabled', null, ICON_SIZE_SMALL, get_lang('This option is not available because this activity is contained by an assessment'));
                     } else {
                         $iconsEdit .= '<a href="'.$url.'&forum='.$forumId.'&action=delete_thread&content=thread&id='
                             .$thread->getIid()."\" onclick=\"javascript:if(!confirm('"
                             .addslashes(api_htmlentities(get_lang('Delete complete thread?'), ENT_QUOTES))
                             ."')) return false;\">"
-                            .Display::return_icon('delete.png', get_lang('Delete'), [], ICON_SIZE_SMALL).'</a>';
+                            .Display::getMdiIcon(ActionIcon::DELETE, 'ch-tool-icon', null, ICON_SIZE_SMALL, get_lang('Delete')).'</a>';
                     }
 
                     $iconsEdit .= returnVisibleInvisibleIcon(
@@ -492,29 +479,28 @@ if (is_array($threads)) {
                         ]
                     );
                     $iconsEdit .= '<a href="'.$viewForumUrl.'&forum='.$forumId.'&action=move_thread&thread='.$threadId.'">'
-                        .Display::return_icon('move.png', get_lang('Move Thread'), [], ICON_SIZE_SMALL)
+                        .Display::getMdiIcon(ActionIcon::MOVE, 'ch-tool-icon', null, ICON_SIZE_SMALL, get_lang('Move Thread'))
                         .'</a>';
                 }
             }
 
-            $iconnotify = 'notification_mail_na.png';
+            $disable = true;
             if (is_array(
                 isset($_SESSION['forum_notification']['thread']) ? $_SESSION['forum_notification']['thread'] : null
                 )
             ) {
                 if (in_array($threadId, $_SESSION['forum_notification']['thread'])) {
-                    $iconnotify = 'notification_mail.png';
+                    $disable = false;
                 }
             }
-            $icon_liststd = 'user.png';
             if (!api_is_anonymous() && api_is_allowed_to_session_edit(false, true)) {
                 $iconsEdit .= '<a href="'.$url.'&forum='.$forumId."&action=notify&content=thread&id={$threadId}".'">'.
-                    Display::return_icon($iconnotify, get_lang('Notify me')).'</a>';
+                    Display::getMdiIcon('email-alert', ($disable ? 'ch-tool-icon-disabled' : 'ch-tool-icon'), '', ICON_SIZE_SMALL, get_lang('Notify me')).'</a>';
             }
 
             if (api_is_allowed_to_edit(null, true) && 'learnpath' != $origin) {
                 $iconsEdit .= '<a href="'.$viewForumUrl.'&forum='.$forumId."&action=liststd&content=thread&id={$threadId}".'">'.
-                    Display::return_icon($icon_liststd, get_lang('Learners list'), [], ICON_SIZE_SMALL)
+                    Display::getMdiIcon(ToolIcon::MEMBER, 'ch-tool-icon', '', ICON_SIZE_SMALL, get_lang('Learners list'))
                     .'</a>';
             }
             $html .= $iconsEdit;
diff --git a/public/main/forum/viewforumcategory.php b/public/main/forum/viewforumcategory.php
index e8e5c5476f..f672225977 100755
--- a/public/main/forum/viewforumcategory.php
+++ b/public/main/forum/viewforumcategory.php
@@ -4,6 +4,8 @@
 
 use Chamilo\CourseBundle\Entity\CForumPost;
 use ChamiloSession as Session;
+use Chamilo\CoreBundle\Component\Utils\ActionIcon;
+use Chamilo\CoreBundle\Component\Utils\ToolIcon;
 
 require_once __DIR__.'/../inc/global.inc.php';
 
@@ -123,12 +125,7 @@ if (!empty($_GET['lp_id']) || !empty($_POST['lp_id'])) {
     $url = '../lp/lp_controller.php?'.api_get_cidreq()
         ."&gradebook=&action=add_item&type=step&lp_id='.$lp_id.'#resource_tab-5";
     $actionLeft .= Display::url(
-        Display::return_icon(
-            'back.png',
-            get_lang('Back to').' '.get_lang('Learning paths'),
-            null,
-            ICON_SIZE_MEDIUM
-        ),
+        Display::getMdiIcon(ActionIcon::BACK, 'ch-tool-icon', '', ICON_SIZE_MEDIUM, get_lang('Back to').' '.get_lang('Learning paths')),
         $url
     );
 }
@@ -137,34 +134,19 @@ if (api_is_allowed_to_edit(false, true)) {
 
     $url = 'index.php?'.api_get_cidreq();
     $actionLeft .= Display::url(
-        Display::return_icon(
-            'back.png',
-            get_lang('Back to').' '.get_lang('Learning paths'),
-            null,
-            ICON_SIZE_MEDIUM
-        ),
+        Display::getMdiIcon(ActionIcon::BACK, 'ch-tool-icon', '', ICON_SIZE_MEDIUM, get_lang('Back to').' '.get_lang('Learning paths')),
         $url
     );
 
     if (is_array($forumCategories) && !empty($forumCategories)) {
         $actionLeft .= Display::url(
-            Display::return_icon(
-                'new_forum.png',
-                get_lang('Add a forum'),
-                null,
-                ICON_SIZE_MEDIUM
-            ),
+            Display::getMdiIcon(ToolIcon::FORUM, 'ch-tool-icon', null, ICON_SIZE_MEDIUM, get_lang('Add a forum')),
             api_get_self().'?'.api_get_cidreq().'&action=add_forum&lp_id='.$lp_id
         );
     }
 
     $actionLeft .= Display::url(
-        Display::return_icon(
-            'new_folder.png',
-            get_lang('Add a forumCategory'),
-            null,
-            ICON_SIZE_MEDIUM
-        ),
+        Display::getMdiIcon(ActionIcon::FOLDER_CREATE, 'ch-tool-icon', null, ICON_SIZE_MEDIUM, get_lang('Add a forumCategory')),
         api_get_self().'?'.api_get_cidreq().'&action=add_category&lp_id='.$lp_id
     );
 }
@@ -212,12 +194,7 @@ if (is_array($forumCategories)) {
             ) {
                 $tools .= '<a href="'.api_get_self().'?'.api_get_cidreq()
                     .'&action=edit_category&content=forumcategory&id='.$categoryId
-                    .'">'.Display::return_icon(
-                        'edit.png',
-                        get_lang('Edit'),
-                        [],
-                        ICON_SIZE_SMALL
-                    )
+                    .'">'.Display::getMdiIcon(ActionIcon::EDIT, 'ch-tool-icon', null, ICON_SIZE_SMALL, get_lang('Edit'))
                     .'</a>';
 
                 $tools .= '<a href="'.api_get_self().'?'.api_get_cidreq()
@@ -228,12 +205,7 @@ if (is_array($forumCategories)) {
                         ENT_QUOTES
                     ))
                     ."')) return false;\">"
-                    .Display::return_icon(
-                        'delete.png',
-                        get_lang('Delete'),
-                        [],
-                        ICON_SIZE_SMALL
-                    )
+                    .Display::getMdiIcon(ActionIcon::DELETE, 'ch-tool-icon', null, ICON_SIZE_SMALL, get_lang('Delete'))
                     .'</a>';
                 $tools .= returnVisibleInvisibleIcon(
                     'forumcategory',
@@ -336,7 +308,7 @@ if (is_array($forumCategories)) {
                         if (api_is_allowed_to_edit(false, true)) {
                             $toolActions .= '<a href="'.api_get_self().'?'.api_get_cidreq()
                                 .'&action=edit_forum&content=forum&id='.$forumId.'">'
-                                .Display::return_icon('edit.png', get_lang('Edit'), [], ICON_SIZE_SMALL)
+                                .Display::getMdiIcon(ActionIcon::EDIT, 'ch-tool-icon', null, ICON_SIZE_SMALL, get_lang('Edit'))
                                 .'</a>';
                             $toolActions .= '<a href="'.api_get_self().'?'.api_get_cidreq()
                                 .'&action=delete_forum&content=forum&id='.$forumId
@@ -344,7 +316,7 @@ if (is_array($forumCategories)) {
                                     api_htmlentities(get_lang('Delete forum ?'), ENT_QUOTES)
                                 )
                                 ."')) return false;\">"
-                                .Display::return_icon('delete.png', get_lang('Delete'), [], ICON_SIZE_SMALL)
+                                .Display::getMdiIcon(ActionIcon::DELETE, 'ch-tool-icon', null, ICON_SIZE_SMALL, get_lang('Delete'))
                                 .'</a>';
 
                             $toolActions .= returnVisibleInvisibleIcon(
diff --git a/public/main/forum/viewthread.php b/public/main/forum/viewthread.php
index 15728c761b..2b2db11d03 100644
--- a/public/main/forum/viewthread.php
+++ b/public/main/forum/viewthread.php
@@ -7,6 +7,8 @@ use Chamilo\CourseBundle\Entity\CForum;
 use Chamilo\CourseBundle\Entity\CForumAttachment;
 use Chamilo\CourseBundle\Entity\CForumPost;
 use Chamilo\CourseBundle\Entity\CForumThread;
+use Chamilo\CoreBundle\Component\Utils\ActionIcon;
+use Chamilo\CoreBundle\Component\Utils\ToolIcon;
 
 require_once __DIR__.'/../inc/global.inc.php';
 
@@ -295,7 +297,7 @@ if ('learnpath' === $origin) {
 $actions = '<span style="float:right;">'.search_link().'</span>';
 if ('learnpath' != $origin) {
     $actions .= '<a href="'.$forumUrl.'viewforum.php?forum='.$forumId.'&'.api_get_cidreq().'">'
-        .Display::return_icon('back.png', get_lang('Back to forum'), '', ICON_SIZE_MEDIUM).'</a>';
+        .Display::getMdiIcon(ActionIcon::BACK, 'ch-tool-icon', null, ICON_SIZE_MEDIUM, get_lang('Back to forum')).'</a>';
 }
 
 // The reply to thread link should only appear when the forum_category is
@@ -313,14 +315,14 @@ if (($current_forum_category &&
         // back link inside lp
         if ('learnpath' == $origin && !empty($threadId)) {
             $actions .= '<a href="'.$forumUrl.'viewforum.php?forum='.$forumId.'&'.api_get_cidreq().'">'
-                .Display::return_icon('back.png', get_lang('Back to forum'), '', ICON_SIZE_MEDIUM).'</a>';
+                .Display::getMdiIcon(ActionIcon::BACK, 'ch-tool-icon', null, ICON_SIZE_MEDIUM, get_lang('Back to forum')).'</a>';
         }
 
         // reply link
         if (!api_is_anonymous() && api_is_allowed_to_session_edit(false, true)) {
             $actions .= '<a href="'.$forumUrl.'reply.php?'.api_get_cidreq().'&forum='.$forumId.'&thread='
                 .$threadId.'&action=replythread">'
-                .Display::return_icon('reply_thread.png', get_lang('Reply to this thread'), '', ICON_SIZE_MEDIUM)
+                .Display::getMdiIcon('reply', 'ch-tool-icon', null, ICON_SIZE_MEDIUM, get_lang('Reply to this thread'))
                 .'</a>';
         }
         // new thread link
@@ -437,7 +439,7 @@ foreach ($posts as $post) {
             $editUrl = api_get_path(WEB_CODE_PATH).'forum/editpost.php?'.api_get_cidreq();
             $editUrl .= "&forum=$forumId&thread=$threadId&post={$post['post_id']}&id_attach=$id_attach";
             $iconEdit .= "<a href='".$editUrl."'>"
-                .Display::return_icon('edit.png', get_lang('Edit'), [], ICON_SIZE_SMALL)
+                .Display::getMdiIcon(ActionIcon::EDIT, 'ch-tool-icon', null, ICON_SIZE_SMALL, get_lang('Edit'))
                 .'</a>';
 
             $editButton = Display::toolbarButton(
@@ -464,7 +466,7 @@ foreach ($posts as $post) {
                 ]
             );
             $iconEdit .= Display::url(
-                Display::return_icon('delete.png', get_lang('Delete'), [], ICON_SIZE_SMALL),
+                Display::getMdiIcon(ActionIcon::DELETE, 'ch-tool-icon', null, ICON_SIZE_SMALL, get_lang('Delete')),
                 $deleteUrl,
                 [
                     'onclick' => "javascript:if(!confirm('"
@@ -501,7 +503,7 @@ foreach ($posts as $post) {
         if ($count > 0) {
             $iconEdit .= '<a href="viewthread.php?'.api_get_cidreq()
                 ."&forum=$forumId&thread=$threadId&action=move&post={$post['post_id']}"
-                .'">'.Display::return_icon('move.png', get_lang('Move post'), [], ICON_SIZE_SMALL).'</a>';
+                .'">'.Display::getMdiIcon(ActionIcon::MOVE, 'ch-tool-icon', null, ICON_SIZE_SMALL, get_lang('Move post')).'</a>';
         }
     }
 
@@ -563,7 +565,7 @@ foreach ($posts as $post) {
                     ."&forum=$forumId&thread=$threadId&action=list&post={$post['post_id']}"
                     ."&user={$userId}&user_id={$userId}"
                     ."&idtextqualify=$current_qualify_thread"
-                    .'" >'.Display::return_icon('quiz.png', get_lang('Grade activity')).'</a>';
+                    .'" >'.Display::getMdiIcon(ToolIcon::QUIZ, 'ch-tool-icon', null, ICON_SIZE_SMALL, get_lang('Grade activity')).'</a>';
             }
         }
     }
@@ -666,7 +668,7 @@ foreach ($posts as $post) {
         'AW:',
         'Aw:',
     ];
-    $replace = '<span>'.Display::getMdiIcon('reply').'</span>';
+    $replace = '<span>'.Display::getMdiIcon('reply', 'ch-tool-icon', '', ICON_SIZE_SMALL).'</span>';
     $post['post_title'] = str_replace($search, $replace, Security::remove_XSS($post['post_title']));
 
     // The post title
@@ -685,7 +687,7 @@ foreach ($posts as $post) {
         $repo = Container::getForumAttachmentRepository();
         /** @var CForumAttachment $attachment */
         foreach ($attachments as $attachment) {
-            $post['post_attachments'] .= Display::getMdiIcon('paperclip');
+            $post['post_attachments'] .= Display::getMdiIcon('paperclip', 'ch-tool-icon', '', ICON_SIZE_SMALL);
             $url = $repo->getResourceFileDownloadUrl($attachment).'?'.api_get_cidreq();
             $post['post_attachments'] .= Display::url($attachment->getFilename(), $url);
             $post['post_attachments'] .= '<span class="forum_attach_comment" >'.$attachment->getComment().'</span>';
@@ -697,7 +699,7 @@ foreach ($posts as $post) {
                     .$attachment->getIid().'&forum='.$forumId.'&thread='.$threadId.'&post='.$post['post_id']
                     .'" onclick="javascript:if(!confirm(\''
                     .addslashes(api_htmlentities(get_lang('Please confirm your choice'), ENT_QUOTES)).'\')) return false;">'
-                    .Display::return_icon('delete.png', get_lang('Delete')).'</a><br />';
+                    .Display::getMdiIcon('delete', 'ch-tool-icon', null, ICON_SIZE_SMALL, get_lang('Delete')).'</a><br />';
             }
         }
     }