diff --git a/Configuration/TCA/Overrides/sys_template.php b/Configuration/TCA/Overrides/sys_template.php
index 85e0ac3..787a578 100644
--- a/Configuration/TCA/Overrides/sys_template.php
+++ b/Configuration/TCA/Overrides/sys_template.php
@@ -1,6 +1,6 @@
 <?php
 
-defined('TYPO3') || die();
+defined('TYPO3_MODE') || die();
 
 \TYPO3\CMS\Core\Utility\ExtensionManagementUtility::addStaticFile(
     'headless_navigations',
diff --git a/README.md b/README.md
index 72eaa1b..499fa29 100644
--- a/README.md
+++ b/README.md
@@ -5,7 +5,7 @@ This extension adds a "navigations" key to the default JSON response, provides c
 ![Navigations array in default response](Documentation/response.png)
 
 ## Requirements
-Extension requires TYPO3 in version at least 11.5.
+Extension requires TYPO3 in version at least 10.4.
 
 ## TYPO3 Installation
 Install extension using composer\
diff --git a/composer.json b/composer.json
index 42d757a..31fc5f2 100644
--- a/composer.json
+++ b/composer.json
@@ -13,10 +13,10 @@
     "GPL-2.0-or-later"
   ],
   "require": {
-    "typo3/cms-core": "^11.5"
+    "typo3/cms-core": "^10.4 || ^11.5"
   },
   "suggest": {
-    "friendsoftypo3/headless": "^2.0"
+    "friendsoftypo3/headless": "^2.0 || ^3.0"
   },
   "extra": {
     "typo3/cms": {
diff --git a/ext_emconf.php b/ext_emconf.php
new file mode 100644
index 0000000..7287e8c
--- /dev/null
+++ b/ext_emconf.php
@@ -0,0 +1,23 @@
+<?php
+
+/** @phpstan-ignore-next-line */
+$EM_CONF[$_EXTKEY] = [
+    'title' => 'Headless Navigations',
+    'description' => 'This extension enhances the EXT:headless json response with three customizable navigations.',
+    'category' => 'misc',
+    'author' => 'Sven Petersen',
+    'author_email' => 'sven@hardanders.de',
+    'state' => 'stable',
+    'clearCacheOnLoad' => 0,
+    'version' => '1.0.0',
+    'constraints' => [
+        'depends' => [
+            'typo3' => '10.4.0-11.5.99',
+        ],
+        'conflicts' => [
+        ],
+        'suggests' => [
+            'headless' => '2.6.0-3.0.99'
+        ],
+    ],
+];