diff --git a/CHANGELOG.md b/CHANGELOG.md
index 74031ce..c9dad0b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,9 @@
+simplyFavicon 2023.10.13
+===========================================================
+* Require Dotclear 2.28
+* Require PHP 8.1
+* Upgrade to Dotclear 2.28
+
 simplyFavicon 2023.08.13
 ===========================================================
 * Require Dotclear 2.27
diff --git a/README.md b/README.md
index 809a03c..9c2c661 100644
--- a/README.md
+++ b/README.md
@@ -1,26 +1,23 @@
 # README
 
-[![Release](https://img.shields.io/badge/release-2023.08.13-a2cbe9.svg)](https://git.dotclear.watch/JcDenis/simplyFavicon/releases)
-[![Date](https://img.shields.io/badge/date-2023.08.13-c44d58.svg)](https://git.dotclear.watch/JcDenis/simplyFavicon/releases)
-[![Dotclear](https://img.shields.io/badge/dotclear-v2.27-137bbb.svg)](https://fr.dotclear.org/download)
+[![Release](https://img.shields.io/badge/release-2023.10.13-a2cbe9.svg)](https://git.dotclear.watch/JcDenis/simplyFavicon/releases)
+![Date](https://img.shields.io/badge/date-2023.10.13-c44d58.svg)
+[![Dotclear](https://img.shields.io/badge/dotclear-v2.28-137bbb.svg)](https://fr.dotclear.org/download)
 [![Dotaddict](https://img.shields.io/badge/dotaddict-official-9ac123.svg)](https://plugins.dotaddict.org/dc2/details/simplyFavicon)
 [![License](https://img.shields.io/github/license/JcDenis/simplyFavicon)](https://git.dotclear.watch/JcDenis/simplyFavicon/blob/master/LICENSE)
 
-## WHAT IS simplyFavicon ?
+## ABOUT
 
-_simplyFavicon_ is a plugin for the open-source 
-web publishing software called Dotclear.
+_pacKman_ is a plugin for the open-source web publishing software called [Dotclear](https://www.dotclear.org).
 
-It adds a favicon to your blog.
+> Add a favicon to your blog.
 
 ## REQUIREMENTS
 
-_simplyFavicon_ requires: 
-
+* Dotclear 2.28
+* PHP 8.1+
+* A readable public directory
 * Administrator permissions
-* Dotclear 2.27
-* PHP 7.4+
-* A readable public directory.
 
 ## USAGE
 
@@ -33,12 +30,13 @@ simplyFavicon add required code to public page to show favicon on browser.
 
 ## LINKS
 
-* License : [GNU GPL v2](https://www.gnu.org/licenses/old-licenses/lgpl-2.0.html)
-* Source & contribution : [Gitea Page](https://git.dotclear.watch/JcDenis/simplyFavicon) or [GitHub Page](https://github.com/JcDenis/simplyFavicon)
-* Packages & details : [Gitea Page](https://git.dotclear.watch/JcDenis/simplyFavicon/releases) or [Dotaddict Page](https://plugins.dotaddict.org/dc2/details/simplyFavicon)
+* [License](https://git.dotclear.watch/JcDenis/simplyFavicon/src/branch/master/LICENSE)
+* [Packages & details](https://git.dotclear.watch/JcDenis/simplyFavicon/releases) (or on [Dotaddict](https://plugins.dotaddict.org/dc2/details/simplyFavicon))
+* [Sources & contributions](https://git.dotclear.watch/JcDenis/simplyFavicon) (or on [GitHub](https://github.com/JcDenis/simplyFavicon))
+* [Issues & security](https://git.dotclear.watch/JcDenis/simplyFavicon/issues) (or on [GitHub](https://github.com/JcDenis/simplyFavicon/issues))
 
 ## CONTRIBUTORS
 
-* Jean-Christian Denis
+* Jean-Christian Denis (author)
 
 You are welcome to contribute to this code.
diff --git a/_define.php b/_define.php
index 26c3049..2f920f5 100644
--- a/_define.php
+++ b/_define.php
@@ -10,9 +10,19 @@
  * @copyright Jean-Christian Denis
  * @copyright GPL-2.0 https://www.gnu.org/licenses/gpl-2.0.html
  */
-if (!defined('DC_RC_PATH')) {
-    return;
-}
+/*
+ * @file
+ * @brief       The simplyFavicon pacKman definition
+ * @ingroup     simplyFavicon
+ *
+ * @defgroup    simplyFavicon Plugin simplyFavicon.
+ *
+ * Multi-agents favicon.
+ *
+ * @author      Jean-Christian Denis
+ * @copyright   GPL-2.0 https://www.gnu.org/licenses/gpl-2.0.html
+ */
+declare(strict_types=1);
 
 $this->registerModule(
     'Simply favicon',
@@ -20,11 +30,9 @@ $this->registerModule(
     'Jean-Christian Denis',
     '2023.08.13',
     [
-        'requires'    => [['core', '2.27']],
-        'permissions' => dcCore::app()->auth->makePermissions([
-            dcCore::app()->auth::PERMISSION_ADMIN,
-        ]),
-        'settings' => [
+        'requires'    => [['core', '2.28']],
+        'permissions' => 'My',
+        'settings'    => [
             'blog' => '#params.' . basename(__DIR__) . '_params',
         ],
         'type'       => 'plugin',
diff --git a/dcstore.xml b/dcstore.xml
index 2a1ccd2..e83cc36 100644
--- a/dcstore.xml
+++ b/dcstore.xml
@@ -2,11 +2,11 @@
 <modules xmlns:da="http://dotaddict.org/da/">
   <module id="simplyFavicon">
     <name>Simply favicon</name>
-    <version>2023.08.13</version>
+    <version>2023.10.13</version>
     <author>Jean-Christian Denis</author>
     <desc>Multi-agents favicon</desc>
-    <file>https://git.dotclear.watch/JcDenis/simplyFavicon/releases/download/v2023.08.13/plugin-simplyFavicon.zip</file>
-    <da:dcmin>2.27</da:dcmin>
+    <file>https://git.dotclear.watch/JcDenis/simplyFavicon/releases/download/v2023.10.13/plugin-simplyFavicon.zip</file>
+    <da:dcmin>2.28</da:dcmin>
     <da:details>https://git.dotclear.watch/JcDenis/simplyFavicon/src/branch/master/README.md</da:details>
     <da:support>https://git.dotclear.watch/JcDenis/simplyFavicon/issues</da:support>
   </module>
diff --git a/src/Backend.php b/src/Backend.php
index 3205198..d23b14a 100644
--- a/src/Backend.php
+++ b/src/Backend.php
@@ -1,21 +1,11 @@
 <?php
-/**
- * @brief simplyFavicon, a plugin for Dotclear 2
- *
- * @package Dotclear
- * @subpackage Plugin
- *
- * @author Jean-Christian Denis
- *
- * @copyright Jean-Christian Denis
- * @copyright GPL-2.0 https://www.gnu.org/licenses/gpl-2.0.html
- */
+
 declare(strict_types=1);
 
 namespace Dotclear\Plugin\simplyFavicon;
 
-use dcCore;
-use dcSettings;
+use Dotclear\App;
+use Dotclear\Core\BlogSettings;
 use Dotclear\Core\Process;
 use Dotclear\Helper\File\Path;
 use Dotclear\Helper\Html\Form\{
@@ -26,6 +16,13 @@ use Dotclear\Helper\Html\Form\{
     Para
 };
 
+/**
+ * @brief   simplyFavicon backend class.
+ * @ingroup simplyFavicon
+ *
+ * @author      Jean-Christian Denis
+ * @copyright   GPL-2.0 https://www.gnu.org/licenses/gpl-2.0.html
+ */
 class Backend extends Process
 {
     public static function init(): bool
@@ -39,18 +36,17 @@ class Backend extends Process
             return false;
         }
 
-        dcCore::app()->addBehaviors([
-            'adminBlogPreferencesFormV2' => function (dcSettings $blog_settings): void {
-                // nullsafe
-                if (is_null(dcCore::app()->blog)) {
+        App::behavior()->addBehaviors([
+            'adminBlogPreferencesFormV2' => function (BlogSettings $blog_settings): void {
+                if (!App::blog()->isDefined()) {
                     return;
                 }
 
                 $exists = [];
-                $path   = Path::fullFromRoot((string) $blog_settings->get('system')->get('public_path'), DC_ROOT);
+                $path   = Path::fullFromRoot((string) $blog_settings->get('system')->get('public_path'), App::config()->dotclearRoot());
                 foreach (['ico', 'png', 'bmp', 'gif', 'jpg', 'mng'] as $ext) {
                     if (file_exists($path . '/favicon.' . $ext)) {
-                        $url      = dcCore::app()->blog->url . dcCore::app()->url->getURLFor('simplyFavicon', $ext);
+                        $url      = App::blog()->url() . App::url()->getURLFor('simplyFavicon', $ext);
                         $exists[] = '<li><a href="' . $url . '">' . $url . '</a></li>';
                     }
                 }
@@ -82,7 +78,7 @@ class Backend extends Process
                 ) .
                 '</div></div><br class="clear" /></div>';
             },
-            'adminBeforeBlogSettingsUpdate' => function (dcSettings $blog_settings): void {
+            'adminBeforeBlogSettingsUpdate' => function (BlogSettings $blog_settings): void {
                 $blog_settings->get('system')->put('simply_favicon', !empty($_POST['simply_favicon']));
             },
         ]);
diff --git a/src/Frontend.php b/src/Frontend.php
index 8deb107..9503ef3 100644
--- a/src/Frontend.php
+++ b/src/Frontend.php
@@ -1,23 +1,20 @@
 <?php
-/**
- * @brief simplyFavicon, a plugin for Dotclear 2
- *
- * @package Dotclear
- * @subpackage Plugin
- *
- * @author Jean-Christian Denis
- *
- * @copyright Jean-Christian Denis
- * @copyright GPL-2.0 https://www.gnu.org/licenses/gpl-2.0.html
- */
+
 declare(strict_types=1);
 
 namespace Dotclear\Plugin\simplyFavicon;
 
-use dcCore;
+use Dotclear\App;
 use Dotclear\Core\Process;
 use Dotclear\Helper\File\Path;
 
+/**
+ * @brief   simplyFavicon frontend class.
+ * @ingroup simplyFavicon
+ *
+ * @author      Jean-Christian Denis
+ * @copyright   GPL-2.0 https://www.gnu.org/licenses/gpl-2.0.html
+ */
 class Frontend extends Process
 {
     public static function init(): bool
@@ -31,16 +28,16 @@ class Frontend extends Process
             return false;
         }
 
-        dcCore::app()->addBehavior('publicHeadContent', function (): void {
-            if (is_null(dcCore::app()->blog) || !dcCore::app()->blog->settings->get('system')->get('simply_favicon')) {
+        App::behavior()->addBehavior('publicHeadContent', function (): void {
+            if (!App::blog()->isDefined() || !App::blog()->settings()->get('system')->get('simply_favicon')) {
                 return;
             }
 
-            $public_path = Path::fullFromRoot(dcCore::app()->blog->settings->get('system')->get('public_path'), DC_ROOT) . '/favicon.';
-            $public_url  = dcCore::app()->blog->url . dcCore::app()->url->getBase('simplyFavicon') . '.';
+            $public_path = Path::fullFromRoot(App::blog()->settings()->get('system')->get('public_path'), App::config()->dotclearRoot()) . '/favicon.';
+            $public_url  = App::blog()->url() . App::url()->getBase('simplyFavicon') . '.';
 
             // ico : IE6
-            if (file_exists($public_path . 'ico') && '?' != substr(dcCore::app()->blog->url, -1)) {
+            if (file_exists($public_path . 'ico') && '?' != substr(App::blog()->url(), -1)) {
                 echo
                 '<link rel="SHORTCUT ICON" type="image/x-icon" href="' . $public_url . 'ico" />' . "\n";
             }
@@ -49,7 +46,7 @@ class Frontend extends Process
                 echo
                 '<link rel="apple-touch-icon" href="' . $public_url . 'png" />' . "\n" .
                 '<link rel="icon" type="image/png" href="' . $public_url . 'png" />' . "\n";
-            // all others
+                // all others
             } else {
                 foreach (UrlHandler::$mimetypes as $ext => $mime) {
                     if (in_array($ext, ['ico', 'png'])) {
diff --git a/src/My.php b/src/My.php
index 4a6e9a1..a5fcf5a 100644
--- a/src/My.php
+++ b/src/My.php
@@ -1,21 +1,32 @@
 <?php
-/**
- * @brief simplyFavicon, a plugin for Dotclear 2
- *
- * @package Dotclear
- * @subpackage Plugin
- *
- * @author Jean-Christian Denis
- *
- * @copyright Jean-Christian Denis
- * @copyright GPL-2.0 https://www.gnu.org/licenses/gpl-2.0.html
- */
+
 declare(strict_types=1);
 
 namespace Dotclear\Plugin\simplyFavicon;
 
+use Dotclear\App;
 use Dotclear\Module\MyPlugin;
 
+/**
+ * @brief   simplyFavicon My helper.
+ * @ingroup simplyFavicon
+ *
+ * @author      Jean-Christian Denis
+ * @copyright   GPL-2.0 https://www.gnu.org/licenses/gpl-2.0.html
+ */
 class My extends MyPlugin
 {
+    protected static function checkCustomContext(int $context): ?bool
+    {
+        return match ($context) {
+            // Limit BACKEND to admin
+            self::BACKEND => App::task()->checkContext('BACKEND')
+                && App::blog()->isDefined()
+                && App::auth()->check(App::auth()->makePermissions([
+                    App::auth()::PERMISSION_ADMIN,
+                ]), App::blog()->id()),
+
+            default => null,
+        };
+    }
 }
diff --git a/src/Prepend.php b/src/Prepend.php
index 0d47b33..a531aa3 100644
--- a/src/Prepend.php
+++ b/src/Prepend.php
@@ -1,22 +1,19 @@
 <?php
-/**
- * @brief simplyFavicon, a plugin for Dotclear 2
- *
- * @package Dotclear
- * @subpackage Plugin
- *
- * @author Jean-Christian Denis
- *
- * @copyright Jean-Christian Denis
- * @copyright GPL-2.0 https://www.gnu.org/licenses/gpl-2.0.html
- */
+
 declare(strict_types=1);
 
 namespace Dotclear\Plugin\simplyFavicon;
 
-use dcCore;
+use Dotclear\App;
 use Dotclear\Core\Process;
 
+/**
+ * @brief   simplyFavicon prepend class.
+ * @ingroup simplyFavicon
+ *
+ * @author      Jean-Christian Denis
+ * @copyright   GPL-2.0 https://www.gnu.org/licenses/gpl-2.0.html
+ */
 class Prepend extends Process
 {
     public static function init(): bool
@@ -30,11 +27,11 @@ class Prepend extends Process
             return false;
         }
 
-        dcCore::app()->url->register(
+        App::url()->register(
             'simplyFavicon',
             'favicon',
             '^favicon.(.*?)$',
-            [UrlHandler::class, 'simplyFaviconUrl']
+            UrlHandler::simplyFaviconUrl(...)
         );
 
         return true;
diff --git a/src/UrlHandler.php b/src/UrlHandler.php
index 5fd05fd..f012663 100644
--- a/src/UrlHandler.php
+++ b/src/UrlHandler.php
@@ -1,25 +1,27 @@
 <?php
-/**
- * @brief simplyFavicon, a plugin for Dotclear 2
- *
- * @package Dotclear
- * @subpackage Plugin
- *
- * @author Jean-Christian Denis
- *
- * @copyright Jean-Christian Denis
- * @copyright GPL-2.0 https://www.gnu.org/licenses/gpl-2.0.html
- */
+
 declare(strict_types=1);
 
 namespace Dotclear\Plugin\simplyFavicon;
 
-use dcCore;
-use dcUrlHandlers;
+use Dotclear\App;
+use Dotclear\Core\Frontend\Url;
 use Dotclear\Helper\File\Path;
 
-class UrlHandler extends dcUrlHandlers
+/**
+ * @brief   simplyFavicon frontend URL handler.
+ * @ingroup simplyFavicon
+ *
+ * @author      Jean-Christian Denis
+ * @copyright   GPL-2.0 https://www.gnu.org/licenses/gpl-2.0.html
+ */
+class UrlHandler extends Url
 {
+    /**
+     * Mime types.
+     *
+     * @var     array<string,string> $mimetypes
+     */
     public static array $mimetypes = [
         'ico' => 'image/x-icon',
         'png' => 'image/png',
@@ -31,14 +33,13 @@ class UrlHandler extends dcUrlHandlers
 
     public static function simplyFaviconUrl(string $arg): void
     {
-        // nullsafe
-        if (is_null(dcCore::app()->blog)) {
+        if (!App::blog()->isDefined()) {
             return;
         }
 
-        $public_path = Path::fullFromRoot(dcCore::app()->blog->settings->get('system')->get('public_path'), DC_ROOT);
+        $public_path = Path::fullFromRoot(App::blog()->settings()->get('system')->get('public_path'), App::config()->dotclearRoot());
 
-        if (dcCore::app()->blog->settings->get('system')->get('simply_favicon')
+        if (App::blog()->settings()->get('system')->get('simply_favicon')
             && !empty($arg)
             && array_key_exists($arg, self::$mimetypes)
             && file_exists($public_path . '/favicon.' . $arg)