diff --git a/assets/css/app.scss b/assets/css/app.scss
index 71ce011e65..1bcb94c9a7 100644
--- a/assets/css/app.scss
+++ b/assets/css/app.scss
@@ -843,6 +843,16 @@ form .field {
   }
 }
 
+.row {
+  @apply flex flex-wrap -mx-4;
+}
+.col-md-4 {
+  @apply w-full md:w-1/3 px-4;
+}
+.col-md-6 {
+  @apply w-full md:w-1/2 px-4;
+}
+
 //@import 'primevue-md-light-indigo/theme.css';
 //@import '~primevue/resources/primevue.min.css';
 //@import '~primeflex/primeflex.css';
diff --git a/package.json b/package.json
index 62e82ae4ef..5347a4f214 100644
--- a/package.json
+++ b/package.json
@@ -39,7 +39,7 @@
     "blueimp-load-image": "^5.16.0",
     "bootstrap-daterangepicker": "^3.1.0",
     "bootstrap-select": "^1.13.18",
-    "chart.js": "^3.9.1",
+    "chart.js": "^4.0.0",
     "colorjs.io": "^0.5.0",
     "cropper": "^4.1.0",
     "datepair.js": "^0.4.17",
diff --git a/public/main/admin/statistics/index.php b/public/main/admin/statistics/index.php
index c2b05148dd..6494818663 100644
--- a/public/main/admin/statistics/index.php
+++ b/public/main/admin/statistics/index.php
@@ -26,7 +26,7 @@ in_array(
     ['recentlogins', 'tools', 'courses', 'coursebylanguage', 'users', 'users_active', 'session_by_date']
 )
 ) {
-    //$htmlHeadXtra[] = api_get_js('chartjs/Chart.min.js');
+    $htmlHeadXtra[] = api_get_build_js('libs/chartjs/chart.js');
     //$htmlHeadXtra[] = api_get_asset('chartjs-plugin-labels/build/chartjs-plugin-labels.min.js');
     // Prepare variables for the JS charts
     $url = $reportName = $reportType = $reportOptions = '';
@@ -828,7 +828,7 @@ switch ($report) {
 
                 $contract = false;
                 $legalAccept = $extraFieldValueUser->get_values_by_handler_and_field_variable($userId, 'legal_accept');
-                if ($legalAccept && isset($legalAccept['value'])) {
+                if ($legalAccept && !empty($legalAccept['value'])) {
                     list($legalId, $legalLanguageId, $legalTime) = explode(':', $legalAccept['value']);
                     if ($legalId) {
                         $contract = true;
@@ -925,7 +925,8 @@ switch ($report) {
                 $data['chart'],
                 'pie',
                 $reportOptions1,
-                'canvas1'
+                'canvas1',
+                false
             );
 
             $scoreDisplay = ScoreDisplay::instance();
@@ -1009,7 +1010,8 @@ switch ($report) {
                     $data['chart'],
                     'pie',
                     $reportOptions2,
-                    'canvas2'
+                    'canvas2',
+                    false
                 );
                 $extraTables .= $data['table'];
             }
@@ -1017,8 +1019,8 @@ switch ($report) {
             // graph 3
             $languages = api_get_languages();
             $all = [];
-            foreach ($languages as $language) {
-                $conditions = ['language' => $language];
+            foreach ($languages as $locale => $language) {
+                $conditions = ['locale' => $locale];
                 $key = $language;
                 if ('2' === substr($language, -1)) {
                     $key = str_replace(2, '', $language);
@@ -1044,7 +1046,8 @@ switch ($report) {
                 $data['chart'],
                 'pie',
                 $reportOptions3,
-                'canvas3'
+                'canvas3',
+                false
             );
             $extraTables .= $data['table'];
 
@@ -1092,7 +1095,8 @@ switch ($report) {
                     $data['chart'],
                     'pie',
                     $reportOptions4,
-                    'canvas4'
+                    'canvas4',
+                    false
                 );
                 $extraTables .= $data['table'];
             }
@@ -1160,7 +1164,8 @@ switch ($report) {
                     $data['chart'],
                     'pie',
                     $reportOptions8,
-                    'canvas8'
+                    'canvas8',
+                    false
                 );
                 $extraTables .= $data['table'];
             }
@@ -1211,7 +1216,8 @@ switch ($report) {
                     $data['chart'],
                     'pie',
                     $reportOptions5,
-                    'canvas5'
+                    'canvas5',
+                    false
                 );
                 $extraTables .= $data['table'];
             }
@@ -1253,7 +1259,8 @@ switch ($report) {
                     $data['chart'],
                     'pie',
                     $reportOptions6,
-                    'canvas6'
+                    'canvas6',
+                    false
                 );
                 $extraTables .= $data['table'];
             }
@@ -1294,12 +1301,13 @@ switch ($report) {
                     $data['chart'],
                     'pie',
                     $reportOptions7,
-                    'canvas7'
+                    'canvas7',
+                    false
                 );
                 $extraTables .= $data['table'];
             }
 
-            $header = Display::page_subheader2(get_lang('TotalNumberOfStudents').': '.$studentCount);
+            $header = Display::page_subheader2(get_lang('Total number of students').': '.$studentCount);
             $content = $header.$extraTables.$graph.$content;
         }
 
@@ -1321,7 +1329,7 @@ switch ($report) {
                 $counts[$minutes] = $row[0];
             }
         }
-        $content = '<div class="pull-left">'.get_lang('UsersOnline').'</div>
+        $content = '<div class="pull-left">'.get_lang('Users online').'</div>
         <div class="pull-right">'.api_get_local_time().'</div>
         <hr />
         <div class="tracking-course-summary">
@@ -1333,7 +1341,7 @@ switch ($report) {
                                 <i class="fa fa-thermometer-4" aria-hidden="true"></i>
                             </span>
                             <div class="tracking-info">
-                                <div class="tracking-text">'.get_lang('UsersOnline').' (3\')</div>
+                                <div class="tracking-text">'.get_lang('Users online').' (3\')</div>
                                 <div class="tracking-number">'.getOnlineUsersCount(3).'</div>
                             </div>
                         </div>
@@ -1346,7 +1354,7 @@ switch ($report) {
                                 <i class="fa fa-thermometer-3" aria-hidden="true"></i>
                             </span>
                             <div class="tracking-info">
-                                <div class="tracking-text">'.get_lang('UsersOnline').' (5\')</div>
+                                <div class="tracking-text">'.get_lang('Users online').' (5\')</div>
                                 <div class="tracking-number">'.getOnlineUsersCount(5).'</div>
                             </div>
                         </div>
@@ -1372,14 +1380,14 @@ switch ($report) {
                                 <i class="fa fa-thermometer-1" aria-hidden="true"></i>
                             </span>
                             <div class="tracking-info">
-                                <div class="tracking-text">'.get_lang('UsersOnline').' (120\')</div>
+                                <div class="tracking-text">'.get_lang('Users online').' (120\')</div>
                                 <div class="tracking-number">'.getOnlineUsersCount(120).'</div>
                             </div>
                         </div>
                     </div>
                 </div>
             </div>
-        <div class="pull-left">'.get_lang('UsersActiveInATest').'</div>
+        <div class="pull-left">'.get_lang('Users active in a test').'</div>
         <hr />
         <div class="row">
             <div class="col-lg-3 col-sm-3">
diff --git a/public/main/inc/lib/statistics.lib.php b/public/main/inc/lib/statistics.lib.php
index bad69a5ca3..71888fbb32 100644
--- a/public/main/inc/lib/statistics.lib.php
+++ b/public/main/inc/lib/statistics.lib.php
@@ -1223,14 +1223,14 @@ class Statistics
                 url: "'.$url.'",
                 type: "POST",
                 success: function(data) {
-                    Chart.defaults.global.responsive = true;
+                    Chart.defaults.responsive = true;
                     var ctx = document.getElementById("'.$elementId.'").getContext("2d");
                     var chart = new Chart(ctx, {
                         type: "'.$type.'",
                         data: data,
                         options: {'.$options.'}
                     });
-                    var title = chart.options.title.text;
+                    var title = chart.options.plugins.title.text;
                     $("#'.$elementId.'_title").html(title);
                     $("#'.$elementId.'_table").html(data.table);
                 }
@@ -1241,14 +1241,18 @@ class Statistics
         return $chartCode;
     }
 
-    public static function getJSChartTemplateWithData($data, $type = 'pie', $options = '', $elementId = 'canvas')
+    public static function getJSChartTemplateWithData($data, $type = 'pie', $options = '', $elementId = 'canvas', $responsive = true)
     {
         $data = json_encode($data);
+        $responsiveValue = $responsive ? 'true' : 'false';
+
         $chartCode = '
         <script>
             $(function() {
-                Chart.defaults.global.responsive = true;
+                Chart.defaults.responsive = '.$responsiveValue.';
                 var ctx = document.getElementById("'.$elementId.'").getContext("2d");
+                ctx.canvas.width = 400;
+                ctx.canvas.height = 400;
                 var chart = new Chart(ctx, {
                     type: "'.$type.'",
                     data: '.$data.',
diff --git a/public/main/inc/lib/usermanager.lib.php b/public/main/inc/lib/usermanager.lib.php
index f5a3d7d378..5ee3d639b6 100644
--- a/public/main/inc/lib/usermanager.lib.php
+++ b/public/main/inc/lib/usermanager.lib.php
@@ -1447,7 +1447,7 @@ class UserManager
                 $urlId = api_get_current_access_url_id();
             }
             $sql .= " INNER JOIN $userUrlTable url_user
-                      ON (user.user_id = url_user.user_id)
+                      ON (user.id = url_user.user_id)
                       WHERE url_user.access_url_id = $urlId";
         } else {
             $sql .= " WHERE 1=1 ";
diff --git a/webpack.config.js b/webpack.config.js
index e94d3909d0..182e270673 100755
--- a/webpack.config.js
+++ b/webpack.config.js
@@ -49,8 +49,6 @@ Encore.setOutputPath("public/build/")
   .enableSassLoader()
   .enableTypeScriptLoader(function (tsConfig) {
     tsConfig.transpileOnly = true
-    //tsConfig.configFile = './tsconfig.json';
-    //tsConfig.exclude = ['/node_modules(?!\\/vuex-composition-helpers)/'];
   })
   .enableVueLoader(() => {}, { version: 3, runtimeCompilerBuild: false })
   .autoProvidejQuery()
@@ -97,12 +95,11 @@ Encore.setOutputPath("public/build/")
       from: "./node_modules/flatpickr/dist/l10n",
       to: "flatpickr/l10n/[name].[ext]",
     },
-    /*,
     {
-        from: './node_modules/mathjax/',
-        pattern: /(MathJax.js)$/,
-        to: 'libs/mathjax/MathJax.js'
-    },*/
+      from: "./node_modules/chart.js/dist/",
+      to: "libs/chartjs/[name].[ext]",
+      pattern: /\.(js|css)$/,
+    }
   ])
   .addPlugin(
     new webpack.DefinePlugin({
@@ -138,21 +135,6 @@ Encore.copyFiles({
   to: "libs/select2/js/[name].[ext]",
 })
 
-// Fix free-jqgrid languages files
-// Encore.addPlugin(new FileManagerPlugin({
-//     onEnd: {
-//         move: [
-//             {
-//                 source: './public/public/build/free-jqgrid/',
-//                 destination: './public/build/free-jqgrid/'
-//             }
-//         ],
-//         delete: [
-//             './public/public/'
-//         ]
-//     }
-// }));
-
 const config = Encore.getWebpackConfig()
 
 module.exports = config