diff --git a/composer.json b/composer.json
index 5c5d532..aec3f8b 100644
--- a/composer.json
+++ b/composer.json
@@ -1,6 +1,6 @@
 {
     "name": "postfinancecheckout/sdk",
-    "version": "3.0.3",
+    "version": "3.1.1",
 	"description": "PostFinance Checkout SDK for PHP",
 	"keywords": [
 		"postfinancecheckout",
diff --git a/lib/ApiClient.php b/lib/ApiClient.php
index 81c665f..792bd4d 100644
--- a/lib/ApiClient.php
+++ b/lib/ApiClient.php
@@ -54,7 +54,7 @@ final class ApiClient {
 	 *
 	 * @var string
 	 */
-	private $userAgent = 'PHP-Client/3.0.3/php';
+	private $userAgent = 'PHP-Client/3.1.1/php';
 
 	/**
 	 * The path to the certificate authority file.
diff --git a/lib/Configuration.php b/lib/Configuration.php
index ad58cf9..20e2bd6 100644
--- a/lib/Configuration.php
+++ b/lib/Configuration.php
@@ -80,7 +80,7 @@ class Configuration
      *
      * @var string
      */
-    protected $userAgent = 'PostFinanceCheckout\Sdk/3.0.3/php';
+    protected $userAgent = 'PostFinanceCheckout\Sdk/3.1.1/php';
 
     /**
      * Debug switch (default set to false)
@@ -388,8 +388,8 @@ public static function toDebugReport()
         $report  = 'PHP SDK (PostFinanceCheckout\Sdk) Debug Report:' . PHP_EOL;
         $report .= '    OS: ' . php_uname() . PHP_EOL;
         $report .= '    PHP Version: ' . PHP_VERSION . PHP_EOL;
-        $report .= '    OpenAPI Spec Version: 3.0.3' . PHP_EOL;
-        $report .= '    SDK Package Version: 3.0.3' . PHP_EOL;
+        $report .= '    OpenAPI Spec Version: 3.1.1' . PHP_EOL;
+        $report .= '    SDK Package Version: 3.1.1' . PHP_EOL;
         $report .= '    Temp Folder Path: ' . self::getDefaultConfiguration()->getTempFolderPath() . PHP_EOL;
 
         return $report;
diff --git a/lib/Model/AbstractTransactionPending.php b/lib/Model/AbstractTransactionPending.php
index 9c37b82..e85cc3a 100644
--- a/lib/Model/AbstractTransactionPending.php
+++ b/lib/Model/AbstractTransactionPending.php
@@ -48,7 +48,7 @@ class AbstractTransactionPending implements ModelInterface, ArrayAccess
       * @var string[]
       */
     protected static $swaggerTypes = [
-        'allowed_payment_method_brands' => '\PostFinanceCheckout\Sdk\Model\PaymentMethodBrand[]',
+        'allowed_payment_method_brands' => 'int[]',
         'allowed_payment_method_configurations' => 'int[]',
         'billing_address' => '\PostFinanceCheckout\Sdk\Model\AddressCreate',
         'completion_behavior' => '\PostFinanceCheckout\Sdk\Model\TransactionCompletionBehavior',
@@ -75,7 +75,7 @@ class AbstractTransactionPending implements ModelInterface, ArrayAccess
       * @var string[]
       */
     protected static $swaggerFormats = [
-        'allowed_payment_method_brands' => null,
+        'allowed_payment_method_brands' => 'int64',
         'allowed_payment_method_configurations' => 'int64',
         'billing_address' => null,
         'completion_behavior' => null,
@@ -360,7 +360,7 @@ public function valid()
     /**
      * Gets allowed_payment_method_brands
      *
-     * @return \PostFinanceCheckout\Sdk\Model\PaymentMethodBrand[]
+     * @return int[]
      */
     public function getAllowedPaymentMethodBrands()
     {
@@ -370,7 +370,7 @@ public function getAllowedPaymentMethodBrands()
     /**
      * Sets allowed_payment_method_brands
      *
-     * @param \PostFinanceCheckout\Sdk\Model\PaymentMethodBrand[] $allowed_payment_method_brands 
+     * @param int[] $allowed_payment_method_brands 
      *
      * @return $this
      */
diff --git a/lib/Model/InvoiceReimbursementWithRefundReference.php b/lib/Model/InvoiceReimbursementWithRefundReference.php
new file mode 100644
index 0000000..95ab72d
--- /dev/null
+++ b/lib/Model/InvoiceReimbursementWithRefundReference.php
@@ -0,0 +1,296 @@
+<?php
+/**
+ * PostFinance Checkout SDK
+ *
+ * This library allows to interact with the PostFinance Checkout payment service.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+namespace PostFinanceCheckout\Sdk\Model;
+use \PostFinanceCheckout\Sdk\ObjectSerializer;
+
+/**
+ * InvoiceReimbursementWithRefundReference model
+ *
+ * @category    Class
+ * @description 
+ * @package     PostFinanceCheckout\Sdk
+ * @author      customweb GmbH
+ * @license     http://www.apache.org/licenses/LICENSE-2.0 Apache License v2
+ */
+class InvoiceReimbursementWithRefundReference extends InvoiceReimbursement 
+{
+    const DISCRIMINATOR = null;
+
+    /**
+      * The original name of the model.
+      *
+      * @var string
+      */
+    protected static $swaggerModelName = 'InvoiceReimbursementWithRefundReference';
+
+    /**
+      * Array of property to type mappings. Used for (de)serialization
+      *
+      * @var string[]
+      */
+    protected static $swaggerTypes = [
+        'refund_merchant_reference' => 'string'
+    ];
+
+    /**
+      * Array of property to format mappings. Used for (de)serialization
+      *
+      * @var string[]
+      */
+    protected static $swaggerFormats = [
+        'refund_merchant_reference' => null
+    ];
+
+    /**
+     * Array of attributes where the key is the local name,
+     * and the value is the original name
+     *
+     * @var string[]
+     */
+    protected static $attributeMap = [
+        'refund_merchant_reference' => 'refundMerchantReference'
+    ];
+
+    /**
+     * Array of attributes to setter functions (for deserialization of responses)
+     *
+     * @var string[]
+     */
+    protected static $setters = [
+        'refund_merchant_reference' => 'setRefundMerchantReference'
+    ];
+
+    /**
+     * Array of attributes to getter functions (for serialization of requests)
+     *
+     * @var string[]
+     */
+    protected static $getters = [
+        'refund_merchant_reference' => 'getRefundMerchantReference'
+    ];
+
+    
+
+
+    /**
+     * Constructor
+     *
+     * @param mixed[] $data Associated array of property values
+     *                      initializing the model
+     */
+    public function __construct(array $data = null)
+    {
+        parent::__construct($data);
+
+        
+        $this->container['refund_merchant_reference'] = isset($data['refund_merchant_reference']) ? $data['refund_merchant_reference'] : null;
+        
+    }
+
+    /**
+     * Show all the invalid properties with reasons.
+     *
+     * @return array invalid properties with reasons
+     */
+    public function listInvalidProperties()
+    {
+        $invalidProperties = parent::listInvalidProperties();
+
+        return $invalidProperties;
+    }
+
+    /**
+     * Array of property to type mappings. Used for (de)serialization
+     *
+     * @return array
+     */
+    public static function swaggerTypes()
+    {
+        return self::$swaggerTypes + parent::swaggerTypes();
+    }
+
+    /**
+     * Array of property to format mappings. Used for (de)serialization
+     *
+     * @return array
+     */
+    public static function swaggerFormats()
+    {
+        return self::$swaggerFormats + parent::swaggerFormats();
+    }
+
+
+    /**
+     * Array of attributes where the key is the local name,
+     * and the value is the original name
+     *
+     * @return array
+     */
+    public static function attributeMap()
+    {
+        return parent::attributeMap() + self::$attributeMap;
+    }
+
+    /**
+     * Array of attributes to setter functions (for deserialization of responses)
+     *
+     * @return array
+     */
+    public static function setters()
+    {
+        return parent::setters() + self::$setters;
+    }
+
+    /**
+     * Array of attributes to getter functions (for serialization of requests)
+     *
+     * @return array
+     */
+    public static function getters()
+    {
+        return parent::getters() + self::$getters;
+    }
+
+    /**
+     * The original name of the model.
+     *
+     * @return string
+     */
+    public function getModelName()
+    {
+        return self::$swaggerModelName;
+    }
+
+    
+
+    /**
+     * Validate all the properties in the model
+     * return true if all passed
+     *
+     * @return bool True if all properties are valid
+     */
+    public function valid()
+    {
+        return count($this->listInvalidProperties()) === 0;
+    }
+
+    
+
+    /**
+     * Gets refund_merchant_reference
+     *
+     * @return string
+     */
+    public function getRefundMerchantReference()
+    {
+        return $this->container['refund_merchant_reference'];
+    }
+
+    /**
+     * Sets refund_merchant_reference
+     *
+     * @param string $refund_merchant_reference 
+     *
+     * @return $this
+     */
+    public function setRefundMerchantReference($refund_merchant_reference)
+    {
+        $this->container['refund_merchant_reference'] = $refund_merchant_reference;
+
+        return $this;
+    }
+    
+    /**
+     * Returns true if offset exists. False otherwise.
+     *
+     * @param integer $offset Offset
+     *
+     * @return boolean
+     */
+    #[\ReturnTypeWillChange]
+    public function offsetExists($offset)
+    {
+        return isset($this->container[$offset]);
+    }
+
+    /**
+     * Gets offset.
+     *
+     * @param integer $offset Offset
+     *
+     * @return mixed
+     */
+    #[\ReturnTypeWillChange]
+    public function offsetGet($offset)
+    {
+        return isset($this->container[$offset]) ? $this->container[$offset] : null;
+    }
+
+    /**
+     * Sets value based on offset.
+     *
+     * @param integer $offset Offset
+     * @param mixed   $value  Value to be set
+     *
+     * @return void
+     */
+    #[\ReturnTypeWillChange]
+    public function offsetSet($offset, $value)
+    {
+        if (is_null($offset)) {
+            $this->container[] = $value;
+        } else {
+            $this->container[$offset] = $value;
+        }
+    }
+
+    /**
+     * Unsets offset.
+     *
+     * @param integer $offset Offset
+     *
+     * @return void
+     */
+    #[\ReturnTypeWillChange]
+    public function offsetUnset($offset)
+    {
+        unset($this->container[$offset]);
+    }
+
+    /**
+     * Gets the string presentation of the object
+     *
+     * @return string
+     */
+    public function __toString()
+    {
+        if (defined('JSON_PRETTY_PRINT')) { // use JSON pretty print
+            return json_encode(
+                ObjectSerializer::sanitizeForSerialization($this),
+                JSON_PRETTY_PRINT
+            );
+        }
+
+        return json_encode(ObjectSerializer::sanitizeForSerialization($this));
+    }
+}
+
+
diff --git a/lib/Model/Transaction.php b/lib/Model/Transaction.php
index 17895b1..a2b2237 100644
--- a/lib/Model/Transaction.php
+++ b/lib/Model/Transaction.php
@@ -51,7 +51,7 @@ class Transaction implements ModelInterface, ArrayAccess
     protected static $swaggerTypes = [
         'accept_header' => 'string',
         'accept_language_header' => 'string',
-        'allowed_payment_method_brands' => '\PostFinanceCheckout\Sdk\Model\PaymentMethodBrand[]',
+        'allowed_payment_method_brands' => 'int[]',
         'allowed_payment_method_configurations' => 'int[]',
         'authorization_amount' => 'float',
         'authorization_environment' => '\PostFinanceCheckout\Sdk\Model\ChargeAttemptEnvironment',
@@ -129,7 +129,7 @@ class Transaction implements ModelInterface, ArrayAccess
     protected static $swaggerFormats = [
         'accept_header' => null,
         'accept_language_header' => null,
-        'allowed_payment_method_brands' => null,
+        'allowed_payment_method_brands' => 'int64',
         'allowed_payment_method_configurations' => 'int64',
         'authorization_amount' => null,
         'authorization_environment' => null,
@@ -776,7 +776,7 @@ public function setAcceptLanguageHeader($accept_language_header)
     /**
      * Gets allowed_payment_method_brands
      *
-     * @return \PostFinanceCheckout\Sdk\Model\PaymentMethodBrand[]
+     * @return int[]
      */
     public function getAllowedPaymentMethodBrands()
     {
@@ -786,7 +786,7 @@ public function getAllowedPaymentMethodBrands()
     /**
      * Sets allowed_payment_method_brands
      *
-     * @param \PostFinanceCheckout\Sdk\Model\PaymentMethodBrand[] $allowed_payment_method_brands 
+     * @param int[] $allowed_payment_method_brands 
      *
      * @return $this
      */
diff --git a/lib/Service/InvoiceReimbursementService.php b/lib/Service/InvoiceReimbursementService.php
index f2a5ae9..5a42215 100644
--- a/lib/Service/InvoiceReimbursementService.php
+++ b/lib/Service/InvoiceReimbursementService.php
@@ -300,7 +300,7 @@ public function readWithHttpInfo($space_id, $id) {
 	 * @throws \PostFinanceCheckout\Sdk\ApiException
 	 * @throws \PostFinanceCheckout\Sdk\VersioningException
 	 * @throws \PostFinanceCheckout\Sdk\Http\ConnectionException
-	 * @return \PostFinanceCheckout\Sdk\Model\InvoiceReimbursement[]
+	 * @return \PostFinanceCheckout\Sdk\Model\InvoiceReimbursementWithRefundReference[]
 	 */
 	public function search($space_id, $query) {
 		return $this->searchWithHttpInfo($space_id, $query)->getData();
@@ -370,16 +370,16 @@ public function searchWithHttpInfo($space_id, $query) {
 				$queryParams,
 				$httpBody,
 				$headerParams,
-				'\PostFinanceCheckout\Sdk\Model\InvoiceReimbursement[]',
+				'\PostFinanceCheckout\Sdk\Model\InvoiceReimbursementWithRefundReference[]',
 				'/invoice-reimbursement-service/search'
 			);
-			return new ApiResponse($response->getStatusCode(), $response->getHeaders(), $this->apiClient->getSerializer()->deserialize($response->getData(), '\PostFinanceCheckout\Sdk\Model\InvoiceReimbursement[]', $response->getHeaders()));
+			return new ApiResponse($response->getStatusCode(), $response->getHeaders(), $this->apiClient->getSerializer()->deserialize($response->getData(), '\PostFinanceCheckout\Sdk\Model\InvoiceReimbursementWithRefundReference[]', $response->getHeaders()));
 		} catch (ApiException $e) {
 			switch ($e->getCode()) {
                 case 200:
                     $data = ObjectSerializer::deserialize(
                         $e->getResponseBody(),
-                        '\PostFinanceCheckout\Sdk\Model\InvoiceReimbursement[]',
+                        '\PostFinanceCheckout\Sdk\Model\InvoiceReimbursementWithRefundReference[]',
                         $e->getResponseHeaders()
                     );
                     $e->setResponseObject($data);