diff --git a/src/Backend.php b/src/Backend.php
index 9815955..7c13a20 100644
--- a/src/Backend.php
+++ b/src/Backend.php
@@ -21,8 +21,9 @@ class Backend extends dcNsProcess
 {
     public static function init(): bool
     {
-        static::$init = My::phpCompliant()
-            && defined('DC_CONTEXT_ADMIN')
+        static::$init = defined('DC_CONTEXT_ADMIN')
+            && !is_null(dcCore::app()->auth) && !is_null(dcCore::app()->blog)
+            && My::phpCompliant()
             && dcCore::app()->auth->isSuperAdmin()
             && dcCore::app()->blog->settings->get(My::id())->get('active');
 
diff --git a/src/BackendBehaviors.php b/src/BackendBehaviors.php
index 55f0309..2109f18 100644
--- a/src/BackendBehaviors.php
+++ b/src/BackendBehaviors.php
@@ -43,7 +43,7 @@ class BackendBehaviors
 
     public static function packmanBeforeCreatePackage(array $module): void
     {
-        if (!dcCore::app()->blog->settings->get(My::id())->get('packman')) {
+        if (is_null(dcCore::app()->blog) || !dcCore::app()->blog->settings->get(My::id())->get('packman')) {
             return;
         }
 
@@ -56,6 +56,10 @@ class BackendBehaviors
 
     public static function modulesToolsHeaders(bool $is_plugin): string
     {
+        if (is_null(dcCore::app()->auth) || is_null(dcCore::app()->auth->user_prefs)) {
+            return '';
+        }
+
         return
             dcPage::jsJson('ts_copied', ['alert' => __('Copied to clipboard')]) .
             dcPage::jsModuleLoad(My::id() . '/js/backend.js') .
@@ -68,16 +72,20 @@ class BackendBehaviors
 
     public static function pluginsToolsTabsV2(): void
     {
-        self::modulesToolsTabs(dcCore::app()->plugins, explode(',', DC_DISTRIB_PLUGINS), dcCore::app()->adminurl->get('admin.plugins'));
+        self::modulesToolsTabs(dcCore::app()->plugins, explode(',', DC_DISTRIB_PLUGINS), (string) dcCore::app()->adminurl?->get('admin.plugins'));
     }
 
     public static function themesToolsTabsV2(): void
     {
-        self::modulesToolsTabs(dcCore::app()->themes, explode(',', DC_DISTRIB_THEMES), dcCore::app()->adminurl->get('admin.blog.theme'));
+        self::modulesToolsTabs(dcCore::app()->themes, explode(',', DC_DISTRIB_THEMES), (string) dcCore::app()->adminurl?->get('admin.blog.theme'));
     }
 
     private static function modulesToolsTabs(dcModules $modules, array $excludes, string $page_url): void
     {
+        if (is_null(dcCore::app()->adminurl) || is_null(dcCore::app()->auth) || is_null(dcCore::app()->auth->user_prefs)) {
+            return;
+        }
+
         $page_url .= '#' . My::id();
         $user_ui_colorsyntax       = dcCore::app()->auth->user_prefs->get('interface')->get('colorsyntax');
         $user_ui_colorsyntax_theme = dcCore::app()->auth->user_prefs->get('interface')->get('colorsyntax_theme');
@@ -303,31 +311,31 @@ class BackendBehaviors
         if (!$module->isDefined()) {
             self::$failed[] = 'unknow module';
         }
-        $rsp->id = $module->get('id');
+        $rsp->insertAttr('id', $module->get('id'));
 
         # name
         if (empty($module->get('name'))) {
             self::$failed[] = 'no module name set in _define.php';
         }
-        $rsp->name($module->get('name'));
+        $rsp->insertNode(new XmlTag('name', $module->get('name')));
 
         # version
         if (empty($module->get('version'))) {
             self::$failed[] = 'no module version set in _define.php';
         }
-        $rsp->version($module->get('version'));
+        $rsp->insertNode(new XmlTag('version', $module->get('version')));
 
         # author
         if (empty($module->get('author'))) {
             self::$failed[] = 'no module author set in _define.php';
         }
-        $rsp->author($module->get('author'));
+        $rsp->insertNode(new XmlTag('author', $module->get('author')));
 
         # desc
         if (empty($module->get('desc'))) {
             self::$failed[] = 'no module description set in _define.php';
         }
-        $rsp->desc($module->get('desc'));
+        $rsp->insertNode(new XmlTag('desc', $module->get('desc')));
 
         # repository
         if (empty($module->get('repository'))) {
@@ -339,7 +347,7 @@ class BackendBehaviors
         if (empty($file_pattern)) {
             self::$failed[] = 'no zip file pattern set in Tweak Store configuration';
         }
-        $rsp->file($file_pattern);
+        $rsp->insertNode(new XmlTag('file', $file_pattern));
 
         # da dc_min or requires core
         if (!empty($module->get('requires')) && is_array($module->get('requires'))) {
diff --git a/src/Config.php b/src/Config.php
index ad945cc..129aa6d 100644
--- a/src/Config.php
+++ b/src/Config.php
@@ -36,6 +36,7 @@ class Config extends dcNsProcess
         static::$init = My::phpCompliant()
             && defined('DC_CONTEXT_ADMIN')
             && defined('DC_CONTEXT_MODULE')
+            && !is_null(dcCore::app()->auth)
             && dcCore::app()->auth->isSuperAdmin();
 
         return static::$init;
@@ -61,7 +62,7 @@ class Config extends dcNsProcess
             dcPage::addSuccessNotice(
                 __('Configuration successfully updated')
             );
-            dcCore::app()->adminurl->redirect(
+            dcCore::app()->adminurl?->redirect(
                 'admin.plugins',
                 ['module' => My::id(), 'conf' => 1, 'redir' => dcCore::app()->admin->__get('list')->getRedir()]
             );
diff --git a/src/Settings.php b/src/Settings.php
index 6fd8cda..2d6d84b 100644
--- a/src/Settings.php
+++ b/src/Settings.php
@@ -15,6 +15,7 @@ declare(strict_types=1);
 namespace Dotclear\Plugin\tweakStores;
 
 use dcCore;
+use Exception;
 
 class Settings
 {
@@ -32,6 +33,10 @@ class Settings
      */
     public function __construct()
     {
+        if (is_null(dcCore::app()->blog)) {
+            throw new Exception('blog is not set');
+        }
+
         $s = dcCore::app()->blog->settings->get(My::id());
 
         $this->active       = (bool) ($s->get('active') ?? false);
@@ -54,6 +59,10 @@ class Settings
      */
     public function writeSetting(string $key, mixed $value): bool
     {
+        if (is_null(dcCore::app()->blog)) {
+            throw new Exception('blog is not set');
+        }
+
         if (property_exists($this, $key) && settype($value, gettype($this->{$key})) === true) {
             dcCore::app()->blog->settings->get(My::id())->drop($key);
             dcCore::app()->blog->settings->get(My::id())->put($key, $value, gettype($this->{$key}), '', true, true);