diff --git a/Block/Checkout/CheckoutConfig.php b/Block/Checkout/CheckoutConfig.php
index 7c7ef2041f2..8d2d2c4f179 100644
--- a/Block/Checkout/CheckoutConfig.php
+++ b/Block/Checkout/CheckoutConfig.php
@@ -33,7 +33,7 @@ public function __construct(
         $this->checkoutSession = $checkoutSession;
     }
 
-    public function getDefaultSelectedMethod(): string
+    public function getDefaultSelectedMethod(): ?string
     {
         $method = $this->checkoutSession->getQuote()->getPayment()->getMethod();
         if ($method) {
diff --git a/composer.json b/composer.json
index e244c32cdf4..9b996542b83 100644
--- a/composer.json
+++ b/composer.json
@@ -1,7 +1,7 @@
 {
   "name": "mollie/magento2",
   "description": "Mollie Payment Module for Magento 2",
-  "version": "2.18.0",
+  "version": "2.18.1",
   "keywords": [
     "mollie",
     "payment",
diff --git a/etc/config.xml b/etc/config.xml
index 0ca7b127238..1205b26a75e 100644
--- a/etc/config.xml
+++ b/etc/config.xml
@@ -3,7 +3,7 @@
     <default>
         <payment>
             <mollie_general>
-                <version>v2.18.0</version>
+                <version>v2.18.1</version>
                 <active>0</active>
                 <enabled>0</enabled>
                 <type>test</type>