diff --git a/CHANGELOG.md b/CHANGELOG.md
index ec43d8e..c44c38c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,10 @@
 CHANGELOG
 =========
 
+6.52.1
+---
+* Add `isDefault` field to Operating System
+
 6.52.0
 ---
 * Add MailAddon API resources
diff --git a/src/Entity/Vps/OperatingSystem.php b/src/Entity/Vps/OperatingSystem.php
index f3a8491..db86f15 100644
--- a/src/Entity/Vps/OperatingSystem.php
+++ b/src/Entity/Vps/OperatingSystem.php
@@ -50,6 +50,11 @@ class OperatingSystem extends AbstractEntity
      */
     protected $installFields = [];
 
+    /**
+     * @var boolean
+     */
+    protected $isDefault = false;
+
     /**
      * @param mixed[] $valueArray
      */
@@ -112,4 +117,9 @@ public function getLicenses(): array
     {
         return $this->licenses;
     }
+
+    public function getIsDefault(): bool
+    {
+        return $this->isDefault;
+    }
 }
diff --git a/src/TransipAPI.php b/src/TransipAPI.php
index 34d00ba..f9e09c8 100644
--- a/src/TransipAPI.php
+++ b/src/TransipAPI.php
@@ -108,7 +108,7 @@
 class TransipAPI
 {
     public const TRANSIP_API_ENDPOINT = "https://api.transip.nl/v6";
-    public const TRANSIP_API_LIBRARY_VERSION = "6.52.0";
+    public const TRANSIP_API_LIBRARY_VERSION = "6.52.1";
     public const TRANSIP_API_DEMO_TOKEN = "eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiIsImp0aSI6ImN3MiFSbDU2eDNoUnkjelM4YmdOIn0.eyJpc3MiOiJhcGkudHJhbnNpcC5ubCIsImF1ZCI6ImFwaS50cmFuc2lwLm5sIiwianRpIjoiY3cyIVJsNTZ4M2hSeSN6UzhiZ04iLCJpYXQiOjE1ODIyMDE1NTAsIm5iZiI6MTU4MjIwMTU1MCwiZXhwIjoyMTE4NzQ1NTUwLCJjaWQiOiI2MDQ0OSIsInJvIjpmYWxzZSwiZ2siOmZhbHNlLCJrdiI6dHJ1ZX0.fYBWV4O5WPXxGuWG-vcrFWqmRHBm9yp0PHiYh_oAWxWxCaZX2Rf6WJfc13AxEeZ67-lY0TA2kSaOCp0PggBb_MGj73t4cH8gdwDJzANVxkiPL1Saqiw2NgZ3IHASJnisUWNnZp8HnrhLLe5ficvb1D9WOUOItmFC2ZgfGObNhlL2y-AMNLT4X7oNgrNTGm-mespo0jD_qH9dK5_evSzS3K8o03gu6p19jxfsnIh8TIVRvNdluYC2wo4qDl5EW5BEZ8OSuJ121ncOT1oRpzXB0cVZ9e5_UVAEr9X3f26_Eomg52-PjrgcRJ_jPIUYbrlo06KjjX2h0fzMr21ZE023Gw";
 
     /**