diff --git a/src/ApiConnectors/ArticleApiConnector.php b/src/ApiConnectors/ArticleApiConnector.php
index b825dbaa..fd2c23a7 100644
--- a/src/ApiConnectors/ArticleApiConnector.php
+++ b/src/ApiConnectors/ArticleApiConnector.php
@@ -37,7 +37,7 @@ public function get(string $code, Office $office): Article
         // Make a request to read a single Article. Set the required values
         $request_article = new Request\Read\Article();
         $request_article
-            ->setOffice($office->getCode())
+            ->setOffice($office)
             ->setCode($code);
 
         // Send the Request document and set the response to this instance.
diff --git a/src/ApiConnectors/BaseApiConnector.php b/src/ApiConnectors/BaseApiConnector.php
index fa33353b..c007426a 100644
--- a/src/ApiConnectors/BaseApiConnector.php
+++ b/src/ApiConnectors/BaseApiConnector.php
@@ -47,6 +47,17 @@ public function __construct(AuthenticatedConnection $connection)
         $this->connection = $connection;
     }
 
+    /**
+     * Will return the current connection
+     *
+     * @return \PhpTwinfield\Secure\AuthenticatedConnection
+     * @throws Exception
+     */
+    public function getConnection(): AuthenticatedConnection
+    {
+        return $this->connection;
+    }
+
     /**
      * @see sendXmlDocument()
      * @throws Exception
@@ -161,4 +172,72 @@ protected function getFinderService(): FinderService
     {
         return $this->connection->getAuthenticatedClient(Services::FINDER());
     }
-}
+
+    /**
+     * Convert options array to an ArrayOfString which is accepted by Twinfield.
+     * 
+     * In some cases you are not allowed to change certain options (such as the dimtype, which should always be DEB when using CustomerApiConnector->ListAll()),
+     * in which case the $forcedOptions parameter will be set by the ApiConnector for this option, which will override any user settings in $options
+     *
+     * @param array $options
+     * @param array $forcedOptions
+     * @return array
+     * @throws Exception
+     */
+    public function convertOptionsToArrayOfString(array $options, array $forcedOptions = []): array {
+        if (isset($options['ArrayOfString'])) {
+            return $options;
+        }
+        
+        $optionsArrayOfString = ['ArrayOfString' => []];
+
+        foreach ($forcedOptions as $key => $value) {
+            unset($options[$key]);
+            $optionsArrayOfString['ArrayOfString'][] = array($key, $value);
+        }
+
+        foreach ($options as $key => $value) {
+            $optionsArrayOfString['ArrayOfString'][] = array($key, $value);
+        }
+
+        return $optionsArrayOfString;
+    }
+
+    /**
+     * Map the response of a listAll to an array of the requested class
+     *
+     * Is used by child ApiConnectors to map a $data object received by the FinderService to one or more new entities of $objectClass
+     * using the methods and attributes in $methodToAttributeMap. Returns an array of $objectClass objects
+     *
+     * @param string $objectClass
+     * @param $data
+     * @param array $methodToAttributeMap
+     * @return array
+     * @throws Exception
+     */
+    public function mapListAll(string $objectClass, $data, array $methodToAttributeMap): array {
+        if ($data->TotalRows == 0) {
+            return [];
+        }
+
+        $objects = [];
+
+        foreach ($data->Items->ArrayOfString as $responseArrayElement) {
+            $object = new $objectClass();
+
+            if (isset($responseArrayElement->string[0])) {
+                $elementArray = $responseArrayElement->string;
+            } else {
+                $elementArray = $responseArrayElement;
+            }
+
+            foreach ($methodToAttributeMap as $key => $method) {
+                $object->$method($elementArray[$key]);
+            }
+
+            $objects[] = $object;
+        }
+
+        return $objects;
+    }
+}
\ No newline at end of file
diff --git a/src/ApiConnectors/CustomerApiConnector.php b/src/ApiConnectors/CustomerApiConnector.php
index 0f42276d..a8cf5acb 100644
--- a/src/ApiConnectors/CustomerApiConnector.php
+++ b/src/ApiConnectors/CustomerApiConnector.php
@@ -37,7 +37,7 @@ public function get(string $code, Office $office): Customer
         // Make a request to read a single customer. Set the required values
         $request_customer = new Request\Read\Customer();
         $request_customer
-            ->setOffice($office->getCode())
+            ->setOffice($office)
             ->setCode($code);
 
         // Send the Request document and set the response to this instance.
diff --git a/src/ApiConnectors/InvoiceApiConnector.php b/src/ApiConnectors/InvoiceApiConnector.php
index 3c9a6219..25806680 100644
--- a/src/ApiConnectors/InvoiceApiConnector.php
+++ b/src/ApiConnectors/InvoiceApiConnector.php
@@ -40,7 +40,7 @@ public function get(string $code, string $invoiceNumber, Office $office)
         $request_invoice
             ->setCode($code)
             ->setNumber($invoiceNumber)
-            ->setOffice($office->getCode());
+            ->setOffice($office);
 
         // Send the Request document and set the response to this instance
         $response = $this->sendXmlDocument($request_invoice);
diff --git a/src/ApiConnectors/SupplierApiConnector.php b/src/ApiConnectors/SupplierApiConnector.php
index f6e692ee..5dd86365 100644
--- a/src/ApiConnectors/SupplierApiConnector.php
+++ b/src/ApiConnectors/SupplierApiConnector.php
@@ -37,7 +37,7 @@ public function get($code, Office $office): Supplier
         // Make a request to read a single customer. Set the required values
         $request_customer = new Request\Read\Supplier();
         $request_customer
-            ->setOffice($office->getCode())
+            ->setOffice($office)
             ->setCode($code);
 
         $response = $this->sendXmlDocument($request_customer);
diff --git a/src/BaseObject.php b/src/BaseObject.php
index d7db7e72..424be098 100644
--- a/src/BaseObject.php
+++ b/src/BaseObject.php
@@ -9,7 +9,7 @@
  *
  * @author Jop peters <jop@mastercoding.nl>
  */
-abstract class BaseObject
+abstract class BaseObject implements HasMessageInterface
 {
     private $result;
     private $messages;
@@ -31,12 +31,11 @@ public function getMessages()
         return $this->messages;
     }
 
-    public function addMessage(Message $message)
+    public function addMessage(Message $message): void
     {
         $this->messages[] = $message;
-
-        return $this;
     }
+    
     public function setMessages($messages)
     {
         $this->messages = $messages;
diff --git a/src/DomDocuments/BaseDocument.php b/src/DomDocuments/BaseDocument.php
index ed9cb33b..2072bb78 100644
--- a/src/DomDocuments/BaseDocument.php
+++ b/src/DomDocuments/BaseDocument.php
@@ -3,6 +3,7 @@
 namespace PhpTwinfield\DomDocuments;
 
 use PhpTwinfield\Enums\PerformanceType;
+use PhpTwinfield\HasMessageInterface;
 use PhpTwinfield\Office;
 use PhpTwinfield\Transactions\TransactionFields\FreeTextFields;
 use PhpTwinfield\Transactions\TransactionFields\StartAndCloseValueFields;
@@ -156,13 +157,24 @@ protected function appendPerformanceTypeFields(\DOMElement $element, $object): v
      * Use this instead of createElement().
      *
      * @param string $tag
-     * @param string $textContent
+     * @param string|null $textContent
+     * @param HasMessageInterface|null $object
+     * @param array $methodToAttributeMap
      * @return \DOMElement
      */
-    final protected function createNodeWithTextContent(string $tag, string $textContent): \DOMElement
+    final protected function createNodeWithTextContent(string $tag, ?string $textContent, ?HasMessageInterface $object = null, array $methodToAttributeMap = []): \DOMElement
     {
         $element = $this->createElement($tag);
-        $element->textContent = $textContent;
+
+        if ($textContent != null) {
+            $element->textContent = $textContent;
+        }
+
+        if (isset($object)) {
+            foreach ($methodToAttributeMap as $attributeName => $method) {
+                $element->setAttribute($attributeName, $object->$method());
+            }
+        }
 
         return $element;
     }
diff --git a/src/HasCodeInterface.php b/src/HasCodeInterface.php
new file mode 100644
index 00000000..e98e19b9
--- /dev/null
+++ b/src/HasCodeInterface.php
@@ -0,0 +1,16 @@
+<?php
+
+namespace PhpTwinfield;
+
+/**
+ * Provides an interface for Objects with getCode functionality
+ *
+ */
+interface HasCodeInterface
+{
+    /**
+     * Gets the code from an object
+     */
+    public function getCode(): ?string;
+    
+}
\ No newline at end of file
diff --git a/src/HasMessageInterface.php b/src/HasMessageInterface.php
new file mode 100644
index 00000000..4da62e58
--- /dev/null
+++ b/src/HasMessageInterface.php
@@ -0,0 +1,20 @@
+<?php
+
+namespace PhpTwinfield;
+
+use PhpTwinfield\Message\Message;
+
+/**
+ * Provides an interface for BaseObject
+ *
+ * @see BaseObject
+ * @see Message
+ *
+ */
+interface HasMessageInterface
+{
+    /**
+     * Adds an error message to an object
+     */
+    public function addMessage(Message $message): void;
+}
\ No newline at end of file
diff --git a/src/Mappers/BaseMapper.php b/src/Mappers/BaseMapper.php
index d98027bb..8e7fcdb5 100644
--- a/src/Mappers/BaseMapper.php
+++ b/src/Mappers/BaseMapper.php
@@ -3,7 +3,13 @@
 namespace PhpTwinfield\Mappers;
 
 use Money\Currency;
+use Money\Money;
+use PhpTwinfield\ApiConnectors\OfficeApiConnector;
+use PhpTwinfield\HasCodeInterface;
+use PhpTwinfield\HasMessageInterface;
+use PhpTwinfield\Message\Message;
 use PhpTwinfield\Office;
+use PhpTwinfield\Secure\AuthenticatedConnection;
 use PhpTwinfield\Util;
 use Webmozart\Assert\Assert;
 
@@ -62,17 +68,166 @@ protected static function getValueFromTag(\DOMDocument $document, string $tag):
         return $element->textContent;
     }
 
-    protected static function getField(\DOMElement $element, string $fieldTagName): ?string
+    protected static function checkForMessage(HasMessageInterface $object, \DOMElement $element): void
+    {
+        if ($element->hasAttribute('msg')) {
+            $message = new Message();
+            $message->setType($element->getAttribute('msgtype'));
+            $message->setMessage($element->getAttribute('msg'));
+            $message->setField($element->nodeName);
+
+            $object->addMessage($message);
+        }
+    }
+
+    protected static function getAttribute(\DOMElement $element, string $fieldTagName, string $attributeName): ?string
+    {
+        $fieldElement = $element->getElementsByTagName($fieldTagName)->item(0);
+
+        if (!isset($fieldElement)) {
+            return null;
+        }
+
+        if ($fieldElement->getAttribute($attributeName) === "") {
+            return null;
+        }
+
+        return $fieldElement->getAttribute($attributeName);
+    }
+
+    protected static function getField(\DOMElement $element, string $fieldTagName, $object = null): ?string
     {
         $fieldElement = $element->getElementsByTagName($fieldTagName)->item(0);
+
         if (!isset($fieldElement)) {
             return null;
         }
 
+        if (isset($object)) {
+            self::checkForMessage($object, $fieldElement);
+        }
+
         if ($fieldElement->textContent === "") {
             return null;
         }
 
         return $fieldElement->textContent;
     }
+    
+    protected static function getOfficeCurrencies(AuthenticatedConnection $connection, Office $office): array
+    {
+        $currencies = ["base" => '', "reporting" => ''];
+        
+        $officeApiConnector = new OfficeApiConnector($connection);
+        $fullOffice = $officeApiConnector->get($office->getCode());
+        
+        if ($fullOffice->getResult() == 1) {
+            $currencies['base'] = Util::objectToStr($fullOffice->getBaseCurrency());
+            $currencies['reporting'] = Util::objectToStr($fullOffice->getReportingCurrency());
+        }
+        
+        return $currencies;
+    }
+
+    protected static function parseDateAttribute(?string $value): ?\DateTimeImmutable
+    {
+        if (false !== strtotime($value)) {
+            return Util::parseDate($value);
+        }
+
+        return null;
+    }
+
+    protected static function parseDateTimeAttribute(?string $value): ?\DateTimeImmutable
+    {
+        if (false !== strtotime($value)) {
+            return Util::parseDateTime($value);
+        }
+
+        return null;
+    }
+
+    protected static function parseEnumAttribute(string $enumClass, ?string $value)
+    {
+        if ($value === null) {
+            return null;
+        }
+
+        try {
+            return new $enumClass($value);
+        } catch (\Exception $e) {
+             return null;
+        }
+    }
+
+    protected static function parseMoneyAttribute(?float $value, ?string $currency): ?Money
+    {
+        if ($value === null || $currency === null) {
+            return null;
+        }
+
+        return Util::parseMoney($value, new Currency($currency));
+    }
+
+    protected static function parseUnknownEntity(HasMessageInterface $object, \DOMElement $element, string $fieldTagName): string
+    {
+        //if (is_a($object, \PhpTwinfield\DimensionGroupDimension::class)) {
+        //    $type = self::getField($element, "type", $object);
+        //} else {
+            $type = self::getAttribute($element, $fieldTagName, "dimensiontype");
+        //}
+
+        switch ($type) {
+            //case "ACT":
+                //return \PhpTwinfield\Activity::class;
+            //case "AST":
+                //return \PhpTwinfield\FixedAsset::class;
+            //case "BAS":
+                //return \PhpTwinfield\GeneralLedger::class;
+            case "CRD":
+                return \PhpTwinfield\Supplier::class;
+            case "DEB":
+                return \PhpTwinfield\Customer::class;
+            //case "KPL":
+                //return \PhpTwinfield\CostCenter::class;
+            //case "PNL":
+                //return \PhpTwinfield\GeneralLedger::class;
+            //case "PRJ":
+                //return \PhpTwinfield\Project::class;
+            default:
+                throw new \InvalidArgumentException("parseUnknownEntity function was unable to determine class name from \"{$type}\"");
+        }
+    }
+
+    /**
+     * Parse a code referring to a Twinfield Entity / PHP Twinfield object
+     *
+     * @param string|null $objectClass
+     * @param HasMessageInterface $object
+     * @param \DOMElement $element
+     * @param string $fieldTagName
+     * @param array $attributes
+     * @return HasCodeInterface
+     */
+    protected static function parseObjectAttribute(?string $objectClass, HasMessageInterface $object, \DOMElement $element, string $fieldTagName, array $attributes = [])
+    {
+        $value = self::getField($element, $fieldTagName, $object);
+        
+        if ($value === null) {
+            return null;
+        }
+        
+        if ($objectClass === null) {
+            $objectClass = self::parseUnknownEntity($object, $element, $fieldTagName);
+        }
+        
+        $object2 = new $objectClass();
+        $object2->setCode($value);
+
+        foreach ($attributes as $attributeName => $method) {
+            $object2->$method(self::getAttribute($element, $fieldTagName, $attributeName));
+        }
+
+        return $object2;
+    }
 }
\ No newline at end of file
diff --git a/src/Request/Catalog/Catalog.php b/src/Request/Catalog/Catalog.php
index cfb21cf8..a56e9b75 100644
--- a/src/Request/Catalog/Catalog.php
+++ b/src/Request/Catalog/Catalog.php
@@ -5,13 +5,13 @@
  * Abstract parent class Catalog. Catalog is the name of the request
  * for LIST. List is a protected term in PHP so all instances of the word
  * catalog are just a replacement.
- * 
+ *
  * All aspects of LIST request require a parent element called 'list'
- * 
+ *
  * The constructor makes this element, appends to the itself.  All requirements
  * to add new elements to this <list> dom element are done through
  * the add() method.
- * 
+ *
  * @package PhpTwinfield
  * @subpackage Request\Catalog
  * @author Leon Rowland <leon@rowland.nl>
@@ -23,7 +23,7 @@ abstract class Catalog extends \DOMDocument
     /**
      * Holds the <list> element that all
      * additional elements should be a child of.
-     * 
+     *
      * @access private
      * @var \DOMElement
      */
@@ -32,7 +32,7 @@ abstract class Catalog extends \DOMDocument
     /**
      * Creates the <list> element and adds it to the property
      * listElement
-     * 
+     *
      * @access public
      */
     public function __construct()
@@ -45,10 +45,10 @@ public function __construct()
 
     /**
      * Adds additional elements to the <list> dom element.
-     * 
+     *
      * See the documentation over what <list> requires to know
      * what additional elements you need.
-     * 
+     *
      * @access protected
      * @param string $element
      * @param mixed $value
diff --git a/src/Request/Catalog/Office.php b/src/Request/Catalog/Office.php
index ac20adec..a055aa20 100644
--- a/src/Request/Catalog/Office.php
+++ b/src/Request/Catalog/Office.php
@@ -3,7 +3,7 @@
 
 /**
  * Used to request a list offices
- * 
+ *
  * @package PhpTwinfield
  * @subpackage Request\Catalog
  * @author Leon Rowland <leon@rowland.nl>
@@ -14,9 +14,9 @@ class Office extends Catalog
 {
     /**
      * Adds the only required element for this request.
-     * 
+     *
      * No other methods exist or are required,
-     * 
+     *
      * @access public
      */
     public function __construct()
@@ -24,4 +24,4 @@ public function __construct()
         parent::__construct();
         $this->add('type', 'offices');
     }
-}
+}
\ No newline at end of file
diff --git a/src/Request/Read/Article.php b/src/Request/Read/Article.php
index 84561c22..151f4be2 100644
--- a/src/Request/Read/Article.php
+++ b/src/Request/Read/Article.php
@@ -1,10 +1,11 @@
 <?php
 namespace PhpTwinfield\Request\Read;
 
+use PhpTwinfield\Office;
+
 /**
- * Used to request a specific custom from a certain
- * office and code.
- * 
+ * Used to request a specific Article from a certain office and code.
+ *
  * @package PhpTwinfield
  * @subpackage Request\Read
  * @author Willem van de Sande <W.vandeSande@MailCoupon.nl>
@@ -14,15 +15,17 @@ class Article extends Read
 {
     /**
      * Sets office and code if they are present.
-     * 
+     *
      * @access public
+     * @param Office|null $office
+     * @param string $code     
      */
-    public function __construct($office = null, $code = null)
+    public function __construct(?Office $office = null, $code = null)
     {
         parent::__construct();
 
         $this->add('type', 'article');
-        
+
         if (null !== $office) {
             $this->setOffice($office);
         }
@@ -31,30 +34,4 @@ public function __construct($office = null, $code = null)
             $this->setCode($code);
         }
     }
-
-    /**
-     * Sets the office code for this Article request.
-     * 
-     * @access public
-     * @param int $office
-     * @return \PhpTwinfield\Request\Read\Article
-     */
-    public function setOffice($office)
-    {
-        $this->add('office', $office);
-        return $this;
-    }
-
-    /**
-     * Sets the code for this Article request.
-     * 
-     * @access public
-     * @param string $code
-     * @return \PhpTwinfield\Request\Read\Article
-     */
-    public function setCode($code)
-    {
-        $this->add('code', $code);
-        return $this;
-    }
 }
diff --git a/src/Request/Read/BrowseDefinition.php b/src/Request/Read/BrowseDefinition.php
index 99e3a7de..47721b22 100644
--- a/src/Request/Read/BrowseDefinition.php
+++ b/src/Request/Read/BrowseDefinition.php
@@ -12,7 +12,7 @@ class BrowseDefinition extends Read
      * @param string $code
      * @param Office|null $office
      */
-    public function __construct(string $code, Office $office = null)
+    public function __construct(string $code, ?Office $office = null)
     {
         parent::__construct();
 
@@ -26,30 +26,4 @@ public function __construct(string $code, Office $office = null)
             $this->setCode($code);
         }
     }
-
-    /**
-     * Sets the office code for this BrowseData request.
-     *
-     * @access public
-     * @param Office $office
-     * @return BrowseDefinition
-     */
-    public function setOffice(Office $office)
-    {
-        $this->add('office', $office->getCode());
-        return $this;
-    }
-
-    /**
-     * Sets the code for this BrowseData request.
-     *
-     * @access public
-     * @param string $code
-     * @return BrowseDefinition
-     */
-    public function setCode($code)
-    {
-        $this->add('code', $code);
-        return $this;
-    }
 }
diff --git a/src/Request/Read/Customer.php b/src/Request/Read/Customer.php
index a7d827b2..a8d9f3fa 100644
--- a/src/Request/Read/Customer.php
+++ b/src/Request/Read/Customer.php
@@ -1,10 +1,12 @@
 <?php
 namespace PhpTwinfield\Request\Read;
 
+use PhpTwinfield\Office;
+
 /**
- * Used to request a specific custom from a certain
+ * Used to request a specific Customer from a certain
  * office and code.
- * 
+ *
  * @package PhpTwinfield
  * @subpackage Request\Read
  * @author Leon Rowland <leon@rowland.nl>
@@ -16,62 +18,24 @@ class Customer extends Read
     /**
      * Sets the <type> to dimensions for the request and
      * sets the dimtype, office and code if they are present.
-     * 
+     *
      * @access public
+     * @param Office|null $office
+     * @param string $code     
      */
-    public function __construct($office = null, $code = null, $dimType = 'DEB')
+    public function __construct(?Office $office = null, $code = null)
     {
         parent::__construct();
 
         $this->add('type', 'dimensions');
-        
+        $this->add('dimtype', 'DEB');
+
         if (null !== $office) {
             $this->setOffice($office);
         }
-        
+
         if (null !== $code) {
             $this->setCode($code);
         }
-        
-        $this->setDimType($dimType);
-    }
-
-    /**
-     * Sets the office code for this customer request.
-     * 
-     * @access public
-     * @param int $office
-     * @return \PhpTwinfield\Request\Read\Customer
-     */
-    public function setOffice($office)
-    {
-        $this->add('office', $office);
-        return $this;
-    }
-
-    /**
-     * Sets the code for this customer request.
-     * 
-     * @access public
-     * @param string $code
-     * @return \PhpTwinfield\Request\Read\Customer
-     */
-    public function setCode($code)
-    {
-        $this->add('code', $code);
-        return $this;
-    }
-    
-    /**
-     * Sets the dimtype for the request.
-     * 
-     * @access public
-     * @param string $dimType
-     * @return \PhpTwinfield\Request\Read\Customer
-     */
-    public function setDimType($dimType)
-    {
-        $this->add('dimtype', $dimType);
-        return $this;
     }
 }
diff --git a/src/Request/Read/Invoice.php b/src/Request/Read/Invoice.php
index 27aec93a..07402a0a 100644
--- a/src/Request/Read/Invoice.php
+++ b/src/Request/Read/Invoice.php
@@ -1,84 +1,59 @@
 <?php
 namespace PhpTwinfield\Request\Read;
 
+use PhpTwinfield\Office;
+
 /**
- * Used to request a specific invoice from a certain
- * code, number and office.
- * 
+ * Used to request a specific Invoice from a certain
+ * code, invoice number and office.
+ *
  * @package PhpTwinfield
  * @subpackage Request\Read
  * @author Leon Rowland <leon@rowland.nl>
- * @copyright (c) 2013, Pronamic 
+ * @copyright (c) 2013, Pronamic
  * @version 0.0.1
  */
 class Invoice extends Read
 {
      /**
      * Sets the <type> to salesinvoice for the request
-     * and sets the office, code and number if they
+     * and sets the office, code and invoice number if they
      * are present.
-     * 
+     *
      * @access public
-     * @param int $office
+     * @param Office|null $office
      * @param string $code
-     * @param int $number
+     * @param int $invoiceNumber
      */
-    public function __construct($office = null, $code = null, $number = null)
+    public function __construct(?Office $office = null, $code = null, $invoiceNumber = null)
     {
         parent::__construct();
 
         $this->add('type', 'salesinvoice');
-        
+
         if (null !== $office) {
             $this->setOffice($office);
         }
-        
+
         if (null !== $code) {
             $this->setCode($code);
         }
-        
-        if (null !== $number) {
-            $this->setNumber($number);
-        }
-    }
 
-     /**
-     * Sets the office code for this salesinvoice
-     * request. It is an optional field.
-     * 
-     * @access public
-     * @param int $office
-     * @return \PhpTwinfield\Request\Read\Invoice
-     */
-    public function setOffice($office)
-    {
-        $this->add('office', $office);
-        return $this;
+        if (null !== $invoiceNumber) {
+            $this->setInvoiceNumber($invoiceNumber);
+        }
     }
 
-     /**
-     * Sets the code for this salesinvoice request.
+    /**
+     * Sets the invoice number for this request.
      *
      * @access public
-     * @param string $code
-     * @return \PhpTwinfield\Request\Read\Invoice
-     */
-    public function setCode($code)
-    {
-        $this->add('code', $code);
-        return $this;
-    }
-
-     /**
-     * Sets the invoicenumber for this request.
-     * 
-     * @access public
-     * @param int $number
+     * @param string $invoiceNumber
      * @return \PhpTwinfield\Request\Read\Invoice
      */
-    public function setNumber($number)
+    public function setInvoiceNumber($invoiceNumber)
     {
-        $this->add('invoicenumber', $number);
+        $this->add('invoicenumber', $invoiceNumber);
         return $this;
     }
 }
diff --git a/src/Request/Read/Read.php b/src/Request/Read/Read.php
index 31b8899c..c3648968 100644
--- a/src/Request/Read/Read.php
+++ b/src/Request/Read/Read.php
@@ -1,16 +1,18 @@
 <?php
 namespace PhpTwinfield\Request\Read;
 
+use PhpTwinfield\Office;
+
 /**
  * Abstract parent class Read. Read is the name for the request component
  * READ.
- * 
+ *
  * All aspects of READ request require a parent element called 'read'
- * 
+ *
  * The construct makes this element, appends to itself. All requirements to
  * add new elements to this <read> dom element are done through the add()
  * method.
- * 
+ *
  * @package PhpTwinfield
  * @subpackage Request\Read
  * @author Leon Rowland <leon@rowland.nl>
@@ -21,8 +23,8 @@ abstract class Read extends \DOMDocument
 {
     /**
      * Holds the <read> element that all
-     * additional elements shoudl be a child of.
-     * 
+     * additional elements should be a child of.
+     *
      * @access private
      * @var \DOMElement
      */
@@ -31,7 +33,7 @@ abstract class Read extends \DOMDocument
     /**
      * Creates the <read> element and adds it to the property
      * readElement
-     * 
+     *
      * @access public
      */
     public function __construct()
@@ -44,10 +46,10 @@ public function __construct()
 
     /**
      * Adds additional elements to the <read> dom element.
-     * 
+     *
      * See the documentation over what <read> requires to know
      * and what additional elements you need.
-     * 
+     *
      * @access protected
      * @param string $element
      * @param mixed $value
@@ -58,4 +60,56 @@ protected function add($element, $value)
         $_element = $this->createElement($element, $value);
         $this->readElement->appendChild($_element);
     }
+
+    /**
+     * Sets the office code for this request.
+     *
+     * @access public
+     * @param Office $office
+     * @return \PhpTwinfield\Request\Read\Read
+     */
+    public function setOffice(Office $office)
+    {
+        $this->add('office', $office);
+        return $this;
+    }
+
+    /**
+     * Sets the code for this request.
+     *
+     * @access public
+     * @param string $code
+     * @return \PhpTwinfield\Request\Read\Read
+     */
+    public function setCode($code)
+    {
+        $this->add('code', $code);
+        return $this;
+    }
+
+    /**
+     * Sets the dimtype for this request.
+     *
+     * @access public
+     * @param string $dimType
+     * @return \PhpTwinfield\Request\Read\Read
+     */
+    public function setDimType($dimType)
+    {
+        $this->add('dimtype', $dimType);
+        return $this;
+    }
+
+    /**
+     * Sets the number for this request.
+     *
+     * @access public
+     * @param string $number
+     * @return \PhpTwinfield\Request\Read\Read
+     */
+    public function setNumber($number)
+    {
+        $this->add('number', $number);
+        return $this;
+    }
 }
diff --git a/src/Request/Read/Supplier.php b/src/Request/Read/Supplier.php
index 2abfc86a..a6ba3d96 100644
--- a/src/Request/Read/Supplier.php
+++ b/src/Request/Read/Supplier.php
@@ -1,10 +1,12 @@
 <?php
 namespace PhpTwinfield\Request\Read;
 
+use PhpTwinfield\Office;
+
 /**
  * Used to request a specific custom from a certain
  * office and code.
- * 
+ *
  * @package PhpTwinfield
  * @subpackage Request\Read
  * @author Leon Rowland <leon@rowland.nl>
@@ -15,63 +17,25 @@ class Supplier extends Read
 {
     /**
      * Sets the <type> to dimensions for the request and
-     * sets the dimtype, office and code if they are present.
-     * 
+     * sets the office and code if they are present.
+     *
      * @access public
+     * @param Office $office
+     * @param string $code
      */
-    public function __construct($office = null, $code = null, $dimType = 'CRD')
+    public function __construct(?Office $office = null, $code = null)
     {
         parent::__construct();
 
         $this->add('type', 'dimensions');
-        
+        $this->add('dimtype', 'CRD');
+
         if (null !== $office) {
             $this->setOffice($office);
         }
-        
+
         if (null !== $code) {
             $this->setCode($code);
         }
-        
-        $this->setDimType($dimType);
-    }
-
-    /**
-     * Sets the office code for this customer request.
-     * 
-     * @access public
-     * @param int $office
-     * @return $this
-     */
-    public function setOffice($office)
-    {
-        $this->add('office', $office);
-        return $this;
-    }
-
-    /**
-     * Sets the code for this customer request.
-     * 
-     * @access public
-     * @param string $code
-     * @return $this
-     */
-    public function setCode($code)
-    {
-        $this->add('code', $code);
-        return $this;
-    }
-    
-    /**
-     * Sets the dimtype for the request.
-     * 
-     * @access public
-     * @param string $dimType
-     * @return $this
-     */
-    public function setDimType($dimType)
-    {
-        $this->add('dimtype', $dimType);
-        return $this;
     }
 }
diff --git a/src/Request/Read/Transaction.php b/src/Request/Read/Transaction.php
index 00bdbad7..5c224d05 100644
--- a/src/Request/Read/Transaction.php
+++ b/src/Request/Read/Transaction.php
@@ -6,7 +6,7 @@
 /**
  * Used to request a specific transaction from a certain
  * office, code and number.
- * 
+ *
  * @package PhpTwinfield
  * @subpackage Request\Read
  * @author Leon Rowland <leon@rowland.nl>
@@ -18,67 +18,28 @@ class Transaction extends Read
     /**
      * Sets the <type> to transaction for the request and
      * sets the office, code and number if they are present.
-     * 
+     *
      * @access public
-     * @param int $office
+     * @param Office $office
      * @param string $code
      * @param int $number
      */
-    public function __construct($office = null, $code = null, $number = null)
+    public function __construct(?Office $office = null, $code = null, $number = null)
     {
         parent::__construct();
-        
+
         $this->add('type', 'transaction');
-        
+
         if (null !== $office) {
             $this->setOffice($office);
         }
-        
+
         if (null !== $code) {
             $this->setCode($code);
         }
-        
+
         if (null !== $number) {
             $this->setNumber($number);
         }
     }
-    
-    /**
-     * Sets the office code for this transaction request.
-     * 
-     * @access public
-     * @param Office $office
-     * @return \PhpTwinfield\Request\Read\Transaction
-     */
-    public function setOffice(Office $office)
-    {
-        $this->add('office', $office->getCode());
-        return $this;
-    }
-    
-    /**
-     * Sets the code for this transaction request.
-     * 
-     * @access public
-     * @param string $code
-     * @return \PhpTwinfield\Request\Read\Transaction
-     */
-    public function setCode($code)
-    {
-        $this->add('code', $code);
-        return $this;
-    }
-    
-    /**
-     * Sets the number for this transaction request
-     * 
-     * @access public
-     * @param int $number
-     * @return \PhpTwinfield\Request\Read\Transaction
-     */
-    public function setNumber($number)
-    {
-        $this->add('number', $number);
-        return $this;
-    }
 }
diff --git a/src/Response/MappedResponseCollection.php b/src/Response/MappedResponseCollection.php
index 0c953615..779e17e7 100644
--- a/src/Response/MappedResponseCollection.php
+++ b/src/Response/MappedResponseCollection.php
@@ -95,4 +95,4 @@ private function countResponses(bool $successful): int
 
         return $count;
     }
-}
+}
\ No newline at end of file
diff --git a/src/Response/Response.php b/src/Response/Response.php
index 43ea9c6e..9e842a82 100644
--- a/src/Response/Response.php
+++ b/src/Response/Response.php
@@ -45,7 +45,7 @@ public static function fromString(string $xml)
 
         return new self($document);
     }
-    
+
     public function __construct(\DOMDocument $responseDocument)
     {
         $this->responseDocument = $responseDocument;
@@ -145,4 +145,4 @@ public function getWarningMessages(): array
     {
         return $this->getMessages('warning');
     }
-}
+}
\ No newline at end of file
diff --git a/src/Secure/OpenIdConnectAuthentication.php b/src/Secure/OpenIdConnectAuthentication.php
index 36ee7a3f..61c5b1db 100644
--- a/src/Secure/OpenIdConnectAuthentication.php
+++ b/src/Secure/OpenIdConnectAuthentication.php
@@ -48,11 +48,13 @@ class OpenIdConnectAuthentication extends AuthenticatedConnection
      * Please note that for most calls an office is mandatory. If you do not supply it
      * you have to pass it with every request, or call setOffice.
      */
-    public function __construct(OAuthProvider $provider, string $refreshToken, ?Office $office)
+    public function __construct(OAuthProvider $provider, string $refreshToken, ?Office $office, string $accessToken = null, string $cluster = null)
     {
         $this->provider     = $provider;
+        $this->accessToken  = $accessToken;
         $this->refreshToken = $refreshToken;
         $this->office       = $office;
+        $this->cluster      = $cluster;
     }
 
     public function setOffice(?Office $office)
@@ -95,8 +97,10 @@ protected function login(): void
             $this->refreshToken();
         }
 
-        $validationResult = $this->validateToken();
-        $this->cluster = $validationResult["twf.clusterUrl"];
+        if ($this->cluster === null) {
+            $validationResult = $this->validateToken();
+            $this->cluster = $validationResult["twf.clusterUrl"];
+        }
     }
 
     /**
diff --git a/src/Services/BaseService.php b/src/Services/BaseService.php
index 8c424909..9391637d 100644
--- a/src/Services/BaseService.php
+++ b/src/Services/BaseService.php
@@ -41,4 +41,9 @@ public function __construct(string $wsdl = null, array $options = [])
 
         parent::__construct($wsdl, $options);
     }
+
+    public function __call($func, $args)
+    {
+        return $this->__soapCall($func, $args);
+    }
 }
diff --git a/src/Services/ProcessXmlService.php b/src/Services/ProcessXmlService.php
index f6204e5f..2c230c94 100644
--- a/src/Services/ProcessXmlService.php
+++ b/src/Services/ProcessXmlService.php
@@ -37,7 +37,7 @@ public function chunk(array $items): array
      *
      * If there is an error in the response, an Exception is thrown, but it can also throw SoapFaults.
      *
-     * Note that you will probably have to chunk the objects into several documents if you want to send many objects. 
+     * Note that you will probably have to chunk the objects into several documents if you want to send many objects.
      *
      * @param \DOMDocument $document
      * @return Response The response from the request
diff --git a/src/Util.php b/src/Util.php
index de8e09c5..cb64e2b3 100644
--- a/src/Util.php
+++ b/src/Util.php
@@ -11,15 +11,36 @@
 
 final class Util
 {
-    public static function formatMoney(Money $money): string
+    /**
+     * Format a money object to string according to Twinfield specifications.
+     *
+     * @param Money|null $money
+     * @return string|null
+     */
+    public static function formatMoney(?Money $money): ?string
     {
+        if ($money === null) {
+            return null;
+        }
+        
         $decimalformatter = new DecimalMoneyFormatter(new ISOCurrencies());
 
         return $decimalformatter->format($money);
     }
 
-    public static function parseMoney(string $moneyString, Currency $currency): Money
+    /**
+     * Parse a money string and Currency object.
+     *
+     * @param string|null $moneyString
+     * @param Currency|null $currency
+     * @return Money|null
+     */
+    public static function parseMoney(?string $moneyString, ?Currency $currency): ?Money
     {
+        if ($moneyString === null || $currency === null) {
+            return null;
+        }
+        
         $parser = new DecimalMoneyParser(new ISOCurrencies());
         return $parser->parse($moneyString, $currency);
     }
@@ -27,23 +48,31 @@ public static function parseMoney(string $moneyString, Currency $currency): Mone
     /**
      * Format a date according to Twinfield specifications.
      *
-     * @param \DateTimeInterface $date
-     * @return string
+     * @param \DateTimeInterface|null $date
+     * @return string|null
      */
-    public static function formatDate(\DateTimeInterface $date): string
+    public static function formatDate(?\DateTimeInterface $date): ?string
     {
+        if ($date === null) {
+            return null;
+        }
+        
         return $date->format("Ymd");
     }
 
     /**
      * Parse a date string from a Twinfield XML.
      *
-     * @param string $dateString
-     * @return \DateTimeImmutable
+     * @param string|null $dateString
+     * @return \DateTimeImmutable|null
      * @throws Exception
      */
-    public static function parseDate(string $dateString): \DateTimeImmutable
+    public static function parseDate(?string $dateString): ?\DateTimeImmutable
     {
+        if ($dateString === null) {
+            return null;
+        }
+        
         $date = \DateTimeImmutable::createFromFormat("Ymd|", $dateString);
 
         if (false === $date) {
@@ -53,15 +82,34 @@ public static function parseDate(string $dateString): \DateTimeImmutable
         return $date;
     }
 
+    /**
+     * Format a date time according to Twinfield specifications.
+     *
+     * @param \DateTimeInterface|null $datetime
+     * @return string|null
+     */
+    public static function formatDateTime(?\DateTimeInterface $datetime): ?string
+    {
+        if ($datetime === null) {
+            return null;
+        }
+        
+        return $datetime->format("YmdHis");
+    }
+
     /**
      * Parse a date time string from a Twinfield XML.
      *
-     * @param string $dateString
-     * @return \DateTimeImmutable
+     * @param string|null $dateString
+     * @return \DateTimeImmutable|null
      * @throws Exception
      */
-    public static function parseDateTime(string $dateString)
+    public static function parseDateTime(?string $dateString): ?\DateTimeImmutable
     {
+        if ($dateString === null) {
+            return null;
+        }
+        
         $date = \DateTimeImmutable::createFromFormat("YmdHis", $dateString);
 
         if (false === $date) {
@@ -72,29 +120,42 @@ public static function parseDateTime(string $dateString)
     }
 
     /**
-     * @param bool $boolean
-     * @return string
+     * @param bool|null $boolean
+     * @return string|null
      */
-    public static function formatBoolean(bool $boolean): string
+    public static function formatBoolean(?bool $boolean): ?string
     {
+        if ($boolean === null) {
+            return null;
+        }
+        
         return $boolean ? "true" : "false";
     }
 
     /**
-     * @param string $input
-     * @return bool
-     * @throws Exception
+     * @param string|null $value
+     * @return bool|null
      */
-    public static function parseBoolean(string $input): bool
+    public static function parseBoolean(?string $value): ?bool
     {
-        switch ($input) {
-            case "true":
-                return true;
-            case "false":
-                return false;
+        if ($value === null) {
+            return null;
         }
+        
+        return filter_var($value, FILTER_VALIDATE_BOOLEAN);
+    }
 
-        throw new Exception("Unknown boolean value \"{$input}\".");
+    /**
+     * @param HasCodeInterface|null $object
+     * @return string|null
+     */
+    public static function objectToStr(?HasCodeInterface $object): ?string
+    {
+        if ($object === null) {
+            return null;
+        }
+        
+        return $object->getCode();
     }
 
     /**