diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9493315..7baedb5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,9 @@
+moreCSS 2.5 -  2023.10.11
+===========================================================
+* Require Dotclear 2.28
+* Require PHP 8.1
+* Upgrade to Dotclear 2.28
+
 moreCSS 2.4 -  2023.08.13
 ===========================================================
 * Require Dotclear 2.27
diff --git a/README.md b/README.md
index afc0786..b8f1c4a 100644
--- a/README.md
+++ b/README.md
@@ -1,26 +1,22 @@
 # README
 
-[![Release](https://img.shields.io/badge/release-2.4-a2cbe9.svg)](https://git.dotclear.watch/JcDenis/moreCSS/releases)
-[![Date](https://img.shields.io/badge/date-2023.08.13-c44d58.svg)](https://git.dotclear.watch/JcDenis/moreCSS/releases)
-[![Dotclear](https://img.shields.io/badge/dotclear-v2.27-137bbb.svg)](https://fr.dotclear.org/download)
+[![Release](https://img.shields.io/badge/release-2.5-a2cbe9.svg)](https://git.dotclear.watch/JcDenis/moreCSS/releases)
+![Date](https://img.shields.io/badge/date-2023.10.11-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/moreCSS)
 [![License](https://img.shields.io/github/license/JcDenis/moreCSS)](https://git.dotclear.watch/JcDenis/moreCSS/blob/master/LICENSE)
 
-## WHAT IS MORECSS ?
+## ABOUT
 
-_moreCSS_ is a plugin for the open-source 
-web publishing software called Dotclear.
+_moreCSS_ is a plugin for the open-source web publishing software called [Dotclear](https://www.dotclear.org).
 
-It helps admin to add more CSS rules to current theme 
-without editing it.
+> It helps admin to add more CSS rules to current theme without editing it.
 
 ## REQUIREMENTS
 
-_moreCSS_ requires: 
-
+* Dotclear 2.28
+* PHP 8.1+
 * content admin permissions to manage CSS
-* Dotclear 2.27
-* PHP 7.4+
 
 ## USAGE
 
@@ -32,16 +28,17 @@ or by adding a favorites icon on dashboard.
 
 ## 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/moreCSS) or [GitHub Page](https://github.com/JcDenis/moreCSS)
-* Packages & details: [Gitea Page](https://git.dotclear.watch/JcDenis/moreCSS/releases) or [Dotaddict Page](https://plugins.dotaddict.org/dc2/details/moreCSS)
-* Discuss & help : [Dotclear forum](http://forum.dotclear.org/viewtopic.php?id=44908)
+* [License](https://git.dotclear.watch/JcDenis/moreCSS/src/branch/master/LICENSE)
+* [Packages & details](https://git.dotclear.watch/JcDenis/moreCSS/releases) (or on [Dotaddict](https://plugins.dotaddict.org/dc2/details/moreCSS))
+* [Sources & contributions](https://git.dotclear.watch/JcDenis/moreCSS) (or on [GitHub](https://github.com/JcDenis/moreCSS))
+* [Issues & security](https://git.dotclear.watch/JcDenis/moreCSS/issues) (or on [GitHub](https://github.com/JcDenis/moreCSS/issues))
+* [Discuss & help](http://forum.dotclear.org/viewtopic.php?id=44908)
 
 ## CONTRIBUTORS
 
 * Osku (author)
 * Pierre Van Glabeke
-* Jean-Christian Denis
+* Jean-Christian Denis (latest)
 
 You are welcome to contribute to this code.
 
diff --git a/_define.php b/_define.php
index 7cb31fd..f73ea66 100644
--- a/_define.php
+++ b/_define.php
@@ -1,32 +1,29 @@
 <?php
-/**
- * @brief moreCSS, a plugin for Dotclear 2
- *
- * @package Dotclear
- * @subpackage Plugin
- *
- * @author Osku and contributors
- *
- * @copyright Jean-Christian Denis
- * @copyright GPL-2.0 https://www.gnu.org/licenses/gpl-2.0.html
- */
-if (!defined('DC_RC_PATH')) {
-    return null;
-}
 
+/**
+ * @file
+ * @brief       The plugin moreCSS definition
+ * @ingroup     moreCSS
+ *
+ * @defgroup    moreCSS Plugin moreCSS.
+ *
+ * Another CSS stylesheet for the active theme.
+ *
+ * @author      Osku (author)
+ * @author      Jean-Christian Denis (latest)
+ * @copyright   GPL-2.0 https://www.gnu.org/licenses/gpl-2.0.html
+ */
 $this->registerModule(
     'Style sheet',
     'Another CSS stylesheet for the active theme',
     'Osku and contributors',
-    '2.4',
+    '2.5',
     [
-        'requires'    => [['core', '2.27']],
-        'permissions' => dcCore::app()->auth->makePermissions([
-            dcCore::app()->auth::PERMISSION_CONTENT_ADMIN,
-        ]),
-        'type'       => 'plugin',
-        'support'    => 'https://git.dotclear.watch/JcDenis/' . basename(__DIR__) . '/issues',
-        'details'    => 'https://git.dotclear.watch/JcDenis/' . basename(__DIR__) . '/src/branch/master/README.md',
-        'repository' => 'https://git.dotclear.watch/JcDenis/' . basename(__DIR__) . '/raw/branch/master/dcstore.xml',
+        'requires'    => [['core', '2.28']],
+        'permissions' => 'My',
+        'type'        => 'plugin',
+        'support'     => 'https://git.dotclear.watch/JcDenis/' . basename(__DIR__) . '/issues',
+        'details'     => 'https://git.dotclear.watch/JcDenis/' . basename(__DIR__) . '/src/branch/master/README.md',
+        'repository'  => 'https://git.dotclear.watch/JcDenis/' . basename(__DIR__) . '/raw/branch/master/dcstore.xml',
     ]
 );
diff --git a/dcstore.xml b/dcstore.xml
index a043cf6..eac5a85 100644
--- a/dcstore.xml
+++ b/dcstore.xml
@@ -2,11 +2,11 @@
 <modules xmlns:da="http://dotaddict.org/da/">
   <module id="moreCSS">
     <name>Style sheet</name>
-    <version>2.4</version>
+    <version>2.5</version>
     <author>Osku and contributors</author>
     <desc>Another CSS stylesheet for the active theme</desc>
-    <file>https://git.dotclear.watch/JcDenis/moreCSS/releases/download/v2.4/plugin-moreCSS.zip</file>
-    <da:dcmin>2.27</da:dcmin>
+    <file>https://git.dotclear.watch/JcDenis/moreCSS/releases/download/v2.5/plugin-moreCSS.zip</file>
+    <da:dcmin>2.28</da:dcmin>
     <da:details>https://git.dotclear.watch/JcDenis/moreCSS/src/branch/master/README.md</da:details>
     <da:support>https://git.dotclear.watch/JcDenis/moreCSS/issues</da:support>
   </module>
diff --git a/src/Backend.php b/src/Backend.php
index fc8ef90..d69b301 100644
--- a/src/Backend.php
+++ b/src/Backend.php
@@ -14,13 +14,18 @@ declare(strict_types=1);
 
 namespace Dotclear\Plugin\moreCSS;
 
-use dcCore;
+use Dotclear\App;
 use Dotclear\Core\Process;
-use Dotclear\Core\Backend\{
-    Favorites,
-    Menus
-};
+use Dotclear\Core\Backend\Favorites;
 
+/**
+ * @brief   moreCSS manage class.
+ * @ingroup moreCSS
+ *
+ * @author      Osku (author)
+ * @author      Jean-Christian Denis (latest)
+ * @copyright   GPL-2.0 https://www.gnu.org/licenses/gpl-2.0.html
+ */
 class Backend extends Process
 {
     public static function init(): bool
@@ -34,15 +39,15 @@ class Backend extends Process
             return false;
         }
 
-        My::addBackendMenuItem(Menus::MENU_BLOG);
+        My::addBackendMenuItem(App::backend()->menus::MENU_BLOG);
 
-        dcCore::app()->addBehavior('adminDashboardFavoritesV2', function (Favorites $favs): void {
+        App::behavior()->addBehavior('adminDashboardFavoritesV2', function (Favorites $favs): void {
             $favs->register(My::id(), [
                 'title'       => My::name(),
                 'url'         => My::manageUrl(),
                 'small-icon'  => My::icons(),
                 'large-icon'  => My::icons(),
-                'permissions' => dcCore::app()->auth->makePermissions([dcCore::app()->auth::PERMISSION_CONTENT_ADMIN]),
+                'permissions' => App::auth()->makePermissions([App::auth()::PERMISSION_CONTENT_ADMIN]),
             ]);
         });
 
diff --git a/src/Frontend.php b/src/Frontend.php
index 617cc65..516f298 100644
--- a/src/Frontend.php
+++ b/src/Frontend.php
@@ -1,23 +1,20 @@
 <?php
-/**
- * @brief moreCSS, a plugin for Dotclear 2
- *
- * @package Dotclear
- * @subpackage Plugin
- *
- * @author Osku and contributors
- *
- * @copyright Jean-Christian Denis
- * @copyright GPL-2.0 https://www.gnu.org/licenses/gpl-2.0.html
- */
+
 declare(strict_types=1);
 
 namespace Dotclear\Plugin\moreCSS;
 
-use dcCore;
-use dcUtils;
+use Dotclear\App;
 use Dotclear\Core\Process;
 
+/**
+ * @brief   moreCSS frontend class.
+ * @ingroup moreCSS
+ *
+ * @author      Osku (author)
+ * @author      Jean-Christian Denis (latest)
+ * @copyright   GPL-2.0 https://www.gnu.org/licenses/gpl-2.0.html
+ */
 class Frontend extends Process
 {
     public static function init(): bool
@@ -27,15 +24,15 @@ class Frontend extends Process
 
     public static function process(): bool
     {
-        if (!self::status() || !dcCore::app()->blog->settings->get('themes')->get('morecss_active')) {
+        if (!self::status() || !App::blog()->settings()->get('themes')->get('morecss_active')) {
             return false;
         }
 
-        dcCore::app()->addBehavior('publicHeadContent', function (): void {
-            $css = (string) base64_decode((string) dcCore::app()->blog->settings->get('themes')->get('morecss_min'));
+        App::behavior()->addBehavior('publicHeadContent', function (): void {
+            $css = (string) base64_decode((string) App::blog()->settings()->get('themes')->get('morecss_min'));
             if (!empty($css)) {
-                echo dcUtils::cssLoad(
-                    dcCore::app()->blog->url . dcCore::app()->url->getURLFor(My::id()),
+                echo App::plugins()->cssLoad(
+                    App::blog()->url() . App::url()->getURLFor(My::id()),
                     'screen',
                     md5($css) //no cache on content change
                 );
diff --git a/src/Install.php b/src/Install.php
index 0339cc9..4f8138e 100644
--- a/src/Install.php
+++ b/src/Install.php
@@ -1,23 +1,21 @@
 <?php
-/**
- * @brief moreCSS, a plugin for Dotclear 2
- *
- * @package Dotclear
- * @subpackage Plugin
- *
- * @author Osku and contributors
- *
- * @copyright Jean-Christian Denis
- * @copyright GPL-2.0 https://www.gnu.org/licenses/gpl-2.0.html
- */
+
 declare(strict_types=1);
 
 namespace Dotclear\Plugin\moreCSS;
 
-use dcCore;
+use Dotclear\App;
 use Dotclear\Core\Process;
 use Exception;
 
+/**
+ * @brief   moreCSS install class.
+ * @ingroup moreCSS
+ *
+ * @author      Osku (author)
+ * @author      Jean-Christian Denis (latest)
+ * @copyright   GPL-2.0 https://www.gnu.org/licenses/gpl-2.0.html
+ */
 class Install extends Process
 {
     public static function init(): bool
@@ -27,19 +25,19 @@ class Install extends Process
 
     public static function process(): bool
     {
-        if (!self::status() || is_null(dcCore::app()->blog)) {
+        if (!self::status() || !App::blog()->isDefined()) {
             return false;
         }
 
         try {
-            $s = dcCore::app()->blog->settings->get('themes');
+            $s = App::blog()->settings()->get('themes');
             $s->put('morecss_active', true, 'boolean', 'Enable additionnal CSS for the active theme', false, true);
             $s->put('morecss', '', 'string', 'Additionnal CSS for the active theme', false, true);
             $s->put('morecss_min', '', 'string', 'Minified addtionnal CSS for the active theme', false, true);
 
             return true;
         } catch (Exception $e) {
-            dcCore::app()->error->add($e->getMessage());
+            App::error()->add($e->getMessage());
         }
 
         return true;
diff --git a/src/Manage.php b/src/Manage.php
index 4f4de29..40e6156 100644
--- a/src/Manage.php
+++ b/src/Manage.php
@@ -1,20 +1,10 @@
 <?php
-/**
- * @brief moreCSS, a plugin for Dotclear 2
- *
- * @package Dotclear
- * @subpackage Plugin
- *
- * @author Osku and contributors
- *
- * @copyright Jean-Christian Denis
- * @copyright GPL-2.0 https://www.gnu.org/licenses/gpl-2.0.html
- */
+
 declare(strict_types=1);
 
 namespace Dotclear\Plugin\moreCSS;
 
-use dcCore;
+use Dotclear\App;
 use Dotclear\Core\Process;
 use Dotclear\Core\Backend\{
     Notices,
@@ -32,6 +22,14 @@ use Dotclear\Helper\Html\Form\{
 use Dotclear\Helper\Html\Html;
 use Exception;
 
+/**
+ * @brief   moreCSS manage class.
+ * @ingroup moreCSS
+ *
+ * @author      Osku (author)
+ * @author      Jean-Christian Denis (latest)
+ * @copyright   GPL-2.0 https://www.gnu.org/licenses/gpl-2.0.html
+ */
 class Manage extends Process
 {
     public static function init(): bool
@@ -45,7 +43,7 @@ class Manage extends Process
             return false;
         }
 
-        $s = dcCore::app()->blog->settings->get('themes');
+        $s = App::blog()->settings()->get('themes');
 
         if (isset($_POST['morecss'])) {
             try {
@@ -70,7 +68,7 @@ class Manage extends Process
                 );
                 My::redirect();
             } catch (Exception $e) {
-                dcCore::app()->error->add($e->getMessage());
+                App::error()->add($e->getMessage());
             }
         }
 
@@ -83,26 +81,26 @@ class Manage extends Process
             return;
         }
 
-        $s = dcCore::app()->blog->settings->get('themes');
+        $s = App::blog()->settings()->get('themes');
 
         Page::openModule(
             My::name(),
             (
-                dcCore::app()->auth->user_prefs->get('interface')->get('colorsyntax') ?
-                Page::jsJson('dotclear_colorsyntax', ['colorsyntax' => dcCore::app()->auth->user_prefs->get('interface')->get('colorsyntax')]) .
-                Page::jsLoadCodeMirror(dcCore::app()->auth->user_prefs->get('interface')->get('colorsyntax_theme'))
+                App::auth()->prefs()->get('interface')->get('colorsyntax') ?
+                Page::jsJson('dotclear_colorsyntax', ['colorsyntax' => App::auth()->prefs()->get('interface')->get('colorsyntax')]) .
+                Page::jsLoadCodeMirror(App::auth()->prefs()->get('interface')->get('colorsyntax_theme'))
                 : ''
             )
         );
 
         echo
         Page::breadcrumb([
-            Html::escapeHTML(dcCore::app()->blog->name) => '',
-            My::name()                                  => '',
+            Html::escapeHTML(App::blog()->name()) => '',
+            My::name()                            => '',
         ]) .
         Notices::getNotices() .
 
-        (new Form('file-form'))->method('post')->action(dcCore::app()->admin->getPageURL())->fields([
+        (new Form('file-form'))->method('post')->action(App::backend()->getPageURL())->fields([
             (new Para())->items([
                 (new Label(__('Style sheet:')))->for('morecss'),
                 (new Textarea('morecss', Html::escapeHTML((string) base64_decode((string) $s->get('morecss')))))->class('maximal')->cols(72)->rows(25),
@@ -112,17 +110,17 @@ class Manage extends Process
                 (new Label(__('Enable additionnal CSS for the active theme'), Label::OUTSIDE_LABEL_AFTER))->for('morecss_active')->class('classic'),
             ]),
             (new Para())->items([
-                dcCore::app()->formNonce(false),
+                App::nonce()->formNonce(),
                 (new Hidden('p', 'moreCSS')),
                 (new Submit(['write']))->value(__('Save') . ' (s)')->accesskey('s'),
             ]),
         ])->render();
 
-        if (dcCore::app()->auth->user_prefs->get('interface')->get('colorsyntax')) {
+        if (App::auth()->prefs()->get('interface')->get('colorsyntax')) {
             echo
             Page::jsJson('theme_editor_mode', ['mode' => 'css']) .
-            Page::jsLoad(dcCore::app()->blog->getPF('themeEditor/js/mode.js')) .
-            Page::jsRunCodeMirror('editor', 'morecss', 'dotclear', dcCore::app()->auth->user_prefs->get('interface')->get('colorsyntax_theme'));
+            Page::jsLoad(App::blog()->getPF('themeEditor/js/mode.js')) .
+            Page::jsRunCodeMirror('editor', 'morecss', 'dotclear', App::auth()->prefs()->get('interface')->get('colorsyntax_theme'));
         }
 
         Page::closeModule();
diff --git a/src/My.php b/src/My.php
index 010702c..a6b1485 100644
--- a/src/My.php
+++ b/src/My.php
@@ -1,31 +1,34 @@
 <?php
-/**
- * @brief moreCSS, a plugin for Dotclear 2
- *
- * @package Dotclear
- * @subpackage Plugin
- *
- * @author Osku and contributors
- *
- * @copyright Jean-Christian Denis
- * @copyright GPL-2.0 https://www.gnu.org/licenses/gpl-2.0.html
- */
+
 declare(strict_types=1);
 
 namespace Dotclear\Plugin\moreCSS;
 
-use dcCore;
+use Dotclear\App;
 use Dotclear\Module\MyPlugin;
 
 /**
- * This module definitions.
+ * @brief   moreCSS My helper.
+ * @ingroup moreCSS
+ *
+ * @author      Osku (author)
+ * @author      Jean-Christian Denis (latest)
+ * @copyright   GPL-2.0 https://www.gnu.org/licenses/gpl-2.0.html
  */
 class My extends MyPlugin
 {
-    public static function checkCustomContext(int $context): ?bool
+    protected static function checkCustomContext(int $context): ?bool
     {
-        return in_array($context, [My::BACKEND, My::MENU]) ?
-            dcCore::app()->auth->check(dcCore::app()->auth->makePermissions([dcCore::app()->auth::PERMISSION_CONTENT_ADMIN]), dcCore::app()->blog->id)
-            : null;
+        return match ($context) {
+            // Allow BACKEND and MANAGE and MENU to also content admin
+            self::MANAGE, self::MENU => App::task()->checkContext('BACKEND')
+                && App::blog()->isDefined()
+                && App::auth()->check(App::auth()->makePermissions([
+                    App::auth()::PERMISSION_ADMIN,
+                    App::auth()::PERMISSION_CONTENT_ADMIN,
+                ]), App::blog()->id()),
+
+            default => null,
+        };
     }
 }
diff --git a/src/Prepend.php b/src/Prepend.php
index 0e65772..1c411f0 100644
--- a/src/Prepend.php
+++ b/src/Prepend.php
@@ -1,22 +1,20 @@
 <?php
-/**
- * @brief moreCSS, a plugin for Dotclear 2
- *
- * @package Dotclear
- * @subpackage Plugin
- *
- * @author Osku and contributors
- *
- * @copyright Jean-Christian Denis
- * @copyright GPL-2.0 https://www.gnu.org/licenses/gpl-2.0.html
- */
+
 declare(strict_types=1);
 
 namespace Dotclear\Plugin\moreCSS;
 
-use dcCore;
+use Dotclear\App;
 use Dotclear\Core\Process;
 
+/**
+ * @brief   moreCSS prepend class.
+ * @ingroup moreCSS
+ *
+ * @author      Osku (author)
+ * @author      Jean-Christian Denis (latest)
+ * @copyright   GPL-2.0 https://www.gnu.org/licenses/gpl-2.0.html
+ */
 class Prepend extends Process
 {
     public static function init(): bool
@@ -30,7 +28,7 @@ class Prepend extends Process
             return false;
         }
 
-        dcCore::app()->url->register(
+        App::url()->register(
             My::id(),
             'morecss.css',
             '^morecss\.css(.*?)$',
@@ -38,7 +36,7 @@ class Prepend extends Process
                 header('Content-Type: text/css; charset=UTF-8');
 
                 echo "/* CSS for plugin moreCss */ \n";
-                echo (string) base64_decode((string) dcCore::app()->blog->settings->get('themes')->get('morecss_min'));
+                echo (string) base64_decode((string) App::blog()->settings()->get('themes')->get('morecss_min'));
 
                 exit;
             }
diff --git a/src/Uninstall.php b/src/Uninstall.php
index a33d25c..c7a4ddb 100644
--- a/src/Uninstall.php
+++ b/src/Uninstall.php
@@ -1,23 +1,20 @@
 <?php
-/**
- * @brief moreCSS, a plugin for Dotclear 2
- *
- * @package Dotclear
- * @subpackage Plugin
- *
- * @author Osku and contributors
- *
- * @copyright Jean-Christian Denis
- * @copyright GPL-2.0 https://www.gnu.org/licenses/gpl-2.0.html
- */
+
 declare(strict_types=1);
 
 namespace Dotclear\Plugin\moreCSS;
 
-use dcCore;
 use Dotclear\Core\Process;
 use Dotclear\Plugin\Uninstaller\Uninstaller;
 
+/**
+ * @brief   moreCSS uninstall class.
+ * @ingroup moreCSS
+ *
+ * @author      Osku (author)
+ * @author      Jean-Christian Denis (latest)
+ * @copyright   GPL-2.0 https://www.gnu.org/licenses/gpl-2.0.html
+ */
 class Uninstall extends Process
 {
     public static function init(): bool
@@ -27,7 +24,7 @@ class Uninstall extends Process
 
     public static function process(): bool
     {
-        if (!self::status() || !dcCore::app()->plugins->moduleExists('Uninstaller')) {
+        if (!self::status()) {
             return false;
         }