diff --git a/src/Client.php b/src/Client.php
index f04f5dce..ba9854d0 100644
--- a/src/Client.php
+++ b/src/Client.php
@@ -34,7 +34,7 @@
 
 class Client
 {
-    public const MAJOR_VERSION = 3;
+    final public const MAJOR_VERSION = 3;
 
     /** @var array<string> */
     private array $baseUrls;
@@ -142,7 +142,7 @@ public function addImage(string $image): AddedImage
 
         try {
             return $this->addImageFromPath($image);
-        } catch (InvalidLocalFileException $e) {
+        } catch (InvalidLocalFileException) {
             // not a local file
         }
 
diff --git a/src/Url/AccessTokenUrl.php b/src/Url/AccessTokenUrl.php
index d7d866f5..4a7c22b4 100644
--- a/src/Url/AccessTokenUrl.php
+++ b/src/Url/AccessTokenUrl.php
@@ -4,7 +4,7 @@
 use GuzzleHttp\Psr7\Uri;
 use GuzzleHttp\Psr7\Utils;
 
-class AccessTokenUrl extends Uri
+class AccessTokenUrl extends Uri implements \Stringable
 {
     private string $privateKey;