diff --git a/CHANGELOG.md b/CHANGELOG.md
index d49e858..9279c3a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 ## [Unreleased]
 
+## 5.0.3
+### Fixed
+* fix #422: undefined array key "HTTP_USER_AGENT"
+
 ## 5.0.2
 ### Fixed
 * fix #413: add user-agent check for memories mobile app
diff --git a/appinfo/info.xml b/appinfo/info.xml
index 7fd8755..ad353fd 100644
--- a/appinfo/info.xml
+++ b/appinfo/info.xml
@@ -30,7 +30,7 @@ Notice
 Because I believe in a free and decentralized Internet, [Gitnet](https://gitnet.fr) is **self-hosted at home**.
 In case of downtime, you can download **Custom Menu** from [here](https://kim.deblan.fr/~side_menu/).
 ]]></description>
-    <version>5.0.2</version>
+    <version>5.0.3</version>
     <licence>agpl</licence>
     <author mail="contact@deblan.fr" homepage="https://www.deblan.fr/">Simon Vieille</author>
     <namespace>SideMenu</namespace>
diff --git a/lib/AppInfo/Application.php b/lib/AppInfo/Application.php
index c255ae3..f4fceb0 100644
--- a/lib/AppInfo/Application.php
+++ b/lib/AppInfo/Application.php
@@ -106,7 +106,7 @@ class Application extends App implements IBootstrap
 
     protected function isEnabled(): bool
     {
-        if (preg_match('/MemoriesNative/', $_SERVER['HTTP_USER_AGENT'])) {
+        if (isset($_SERVER["HTTP_USER_AGENT"]) && preg_match('/MemoriesNative/', $_SERVER['HTTP_USER_AGENT'])) {
             return false;
         }