diff --git a/composer.json b/composer.json
index 602c2179..0af26520 100755
--- a/composer.json
+++ b/composer.json
@@ -1,7 +1,7 @@
 {
   "name": "yoti/yoti-php-sdk",
   "description": "Yoti SDK for quickly integrating your PHP backend with Yoti",
-  "version": "4.2.0",
+  "version": "4.2.1",
   "keywords": [
     "yoti",
     "sdk"
diff --git a/src/Constants.php b/src/Constants.php
index f784e2ec..d8a8ceaa 100644
--- a/src/Constants.php
+++ b/src/Constants.php
@@ -25,7 +25,7 @@ class Constants
     public const SDK_IDENTIFIER = 'PHP';
 
     /** Default SDK version */
-    public const SDK_VERSION = '4.2.0';
+    public const SDK_VERSION = '4.2.1';
 
     /** Base url for connect page (user will be redirected to this page eg. baseurl/app-id) */
     public const CONNECT_BASE_URL = 'https://www.yoti.com/connect';