diff --git a/Application/Model/AbstractClasses/pdfDocuments_generic.php b/Application/Model/AbstractClasses/pdfDocuments_generic.php
index fb1ab7e..4d7645e 100644
--- a/Application/Model/AbstractClasses/pdfDocuments_generic.php
+++ b/Application/Model/AbstractClasses/pdfDocuments_generic.php
@@ -17,13 +17,25 @@
 
 namespace D3\PdfDocuments\Application\Model\AbstractClasses;
 
-use D3\PdfDocuments\Application\Model\Interfaces\pdfdocuments_generic as genericInterface;
+use D3\PdfDocuments\Application\Model\Interfaces\pdfdocuments_generic_interface as genericInterface;
 use OxidEsales\Eshop\Core\Registry;
 use Smarty;
 use Spipu\Html2Pdf\Html2Pdf;
 
 abstract class pdfDocuments_generic implements genericInterface
 {
+    /** @var Smarty  */
+    public $oSmarty;
+
+    /**
+     * pdfDocuments_generic constructor.
+     */
+    public function __construct()
+    {
+        /** @var Smarty $oSmarty */
+        $this->oSmarty = Registry::getUtilsView()->getSmarty();
+    }
+
     /**
      * @param        $sFilename
      * @param int    $iSelLang
@@ -33,25 +45,17 @@ abstract class pdfDocuments_generic implements genericInterface
     {
         $sFilename = $this->getFilename( $sFilename);
 
-        $oPdf = call_user_func_array('oxNew', array_merge([Html2Pdf::class], $this->getPdfProperties()));
-        //$oPdf = oxNew(Html2Pdf::class, 'P', 'A4', 'de');
+        $oPdf = oxNew(Html2Pdf::class, ...$this->getPdfProperties());
         $oPdf->writeHTML($this->getHTMLContent($iSelLang));
         $oPdf->output($sFilename, $target);
     }
 
-    /**
-     * @param Smarty $smarty
-     *
-     * @return Smarty
-     */
-    public function setSmartyVars($smarty)
+    public function setSmartyVars()
     {
-        $smarty->assign('oConfig', Registry::getSession()->getConfig());
-        $smarty->assign('oViewConf', Registry::getSession()->getConfig()->getActiveView()->getViewConfig());
-        $smarty->assign('shop', Registry::getSession()->getConfig()->getActiveShop());
-        $smarty->assign('lang', Registry::getLang());
-
-        return $smarty;
+        $this->oSmarty->assign('oConfig', Registry::getSession()->getConfig());
+        $this->oSmarty->assign('oViewConf', Registry::getSession()->getConfig()->getActiveView()->getViewConfig());
+        $this->oSmarty->assign('shop', Registry::getSession()->getConfig()->getActiveShop());
+        $this->oSmarty->assign('lang', Registry::getLang());
     }
 
     /**
@@ -73,15 +77,12 @@ abstract class pdfDocuments_generic implements genericInterface
     {
         $lang = Registry::getLang();
 
-        /** @var Smarty $oSmarty */
-        $oSmarty = Registry::getUtilsView()->getSmarty();
-
         $currTplLang = $lang->getTplLanguage();
         $lang->setTplLanguage($iSelLang);
 
-        $oSmarty = $this->setSmartyVars($oSmarty);
+        $this->setSmartyVars();
 
-        $content = $oSmarty->fetch($this->getTemplate());
+        $content = $this->oSmarty->fetch($this->getTemplate());
 
         $lang->setTplLanguage($currTplLang);
 
diff --git a/Application/Model/AbstractClasses/pdfDocuments_order.php b/Application/Model/AbstractClasses/pdfDocuments_order.php
index 7e4f89e..f28f5be 100644
--- a/Application/Model/AbstractClasses/pdfDocuments_order.php
+++ b/Application/Model/AbstractClasses/pdfDocuments_order.php
@@ -17,11 +17,10 @@
 
 namespace D3\PdfDocuments\Application\Model\AbstractClasses;
 
-use D3\PdfDocuments\Application\Model\Interfaces\pdfdocuments_order as orderInterface;
+use D3\PdfDocuments\Application\Model\Interfaces\pdfdocuments_order_interface as orderInterface;
 use \OxidEsales\Eshop\Application\Model\Order;
 use OxidEsales\Eshop\Application\Model\Payment;
 use OxidEsales\Eshop\Application\Model\User;
-use Smarty;
 
 abstract class pdfDocuments_order extends pdfDocuments_generic implements orderInterface
 {
@@ -44,26 +43,19 @@ abstract class pdfDocuments_order extends pdfDocuments_generic implements orderI
         return $this->oOrder;
     }
 
-    /**
-     * @param Smarty $smarty
-     *
-     * @return Smarty
-     */
-    public function setSmartyVars($smarty)
+    public function setSmartyVars()
     {
-        $smarty = parent::setSmartyVars($smarty);
+        parent::setSmartyVars();
 
-        $smarty->assign('order', $this->getOrder());
+        $this->oSmarty->assign('order', $this->getOrder());
 
         $oUser = oxNew(User::Class);
         $oUser->load($this->getOrder()->getFieldData('oxuserid'));
-        $smarty->assign('user', $oUser);
+        $this->oSmarty->assign('user', $oUser);
 
         $oPayment = oxNew(Payment::class);
         $oPayment->load($this->getOrder()->getFieldData('oxpaymenttype'));
-        $smarty->assign('payment', $oPayment);
-
-        return $smarty;
+        $this->oSmarty->assign('payment', $oPayment);
     }
 
     /**
diff --git a/Application/Model/Documents/invoicePdf.php b/Application/Model/Documents/invoicePdf.php
index d7e019b..1c9e397 100644
--- a/Application/Model/Documents/invoicePdf.php
+++ b/Application/Model/Documents/invoicePdf.php
@@ -18,9 +18,9 @@
 namespace D3\PdfDocuments\Modules\Application\Model\Documents;
 
 use D3\PdfDocuments\Application\Model\AbstractClasses\pdfDocuments_order;
-use D3\PdfDocuments\Application\Model\Interfaces\pdfdocuments_orderinvoice;
+use D3\PdfDocuments\Application\Model\Interfaces\pdfdocuments_orderinvoice_interface;
 
-class invoicePdf extends pdfDocuments_order implements pdfdocuments_orderinvoice
+class invoicePdf extends pdfDocuments_order implements pdfdocuments_orderinvoice_interface
 {
     protected $blIsNewOrder = false;
 
diff --git a/Application/Model/Interfaces/pdfdocuments_generic.php b/Application/Model/Interfaces/pdfdocuments_generic_interface.php
similarity index 95%
rename from Application/Model/Interfaces/pdfdocuments_generic.php
rename to Application/Model/Interfaces/pdfdocuments_generic_interface.php
index 607aa77..924dd6b 100644
--- a/Application/Model/Interfaces/pdfdocuments_generic.php
+++ b/Application/Model/Interfaces/pdfdocuments_generic_interface.php
@@ -17,7 +17,7 @@
 
 namespace D3\PdfDocuments\Application\Model\Interfaces;
 
-interface pdfdocuments_generic 
+interface pdfdocuments_generic_interface
 {
     /**
      * @return string
diff --git a/Application/Model/Interfaces/pdfdocuments_order.php b/Application/Model/Interfaces/pdfdocuments_order_interface.php
similarity index 90%
rename from Application/Model/Interfaces/pdfdocuments_order.php
rename to Application/Model/Interfaces/pdfdocuments_order_interface.php
index 4a562a2..1a28938 100644
--- a/Application/Model/Interfaces/pdfdocuments_order.php
+++ b/Application/Model/Interfaces/pdfdocuments_order_interface.php
@@ -19,7 +19,7 @@ namespace D3\PdfDocuments\Application\Model\Interfaces;
 
 use OxidEsales\Eshop\Application\Model\Order;
 
-interface pdfdocuments_order extends pdfdocuments_generic
+interface pdfdocuments_order_interface extends pdfdocuments_generic_interface
 {
     /**
      * @param Order $order
diff --git a/Application/Model/Interfaces/pdfdocuments_orderinvoice.php b/Application/Model/Interfaces/pdfdocuments_orderinvoice_interface.php
similarity index 88%
rename from Application/Model/Interfaces/pdfdocuments_orderinvoice.php
rename to Application/Model/Interfaces/pdfdocuments_orderinvoice_interface.php
index 9dcc216..91f7ece 100644
--- a/Application/Model/Interfaces/pdfdocuments_orderinvoice.php
+++ b/Application/Model/Interfaces/pdfdocuments_orderinvoice_interface.php
@@ -17,7 +17,7 @@
 
 namespace D3\PdfDocuments\Application\Model\Interfaces;
 
-interface pdfdocuments_orderinvoice extends pdfdocuments_order 
+interface pdfdocuments_orderinvoice_interface extends pdfdocuments_order_interface
 {
     public function setInvoiceNumber();
   
diff --git a/Modules/Application/Model/d3_Order_PdfDocuments.php b/Modules/Application/Model/d3_Order_PdfDocuments.php
index 9a8de66..53deaae 100644
--- a/Modules/Application/Model/d3_Order_PdfDocuments.php
+++ b/Modules/Application/Model/d3_Order_PdfDocuments.php
@@ -17,7 +17,7 @@
 
 namespace D3\PdfDocuments\Modules\Application\Model;
 
-use D3\PdfDocuments\Application\Model\Interfaces\pdfdocuments_order as OrderPdfInterface;
+use D3\PdfDocuments\Application\Model\Interfaces\pdfdocuments_orderInterface as OrderPdfInterface;
 use D3\PdfDocuments\Modules\Application\Model\Documents\invoicePdf;
 use D3\PdfDocuments\Modules\Application\Model\Documents\deliverynotePdf;
 use OxidEsales\Eshop\Core\Registry;
diff --git a/composer.json b/composer.json
index 9923320..3888376 100644
--- a/composer.json
+++ b/composer.json
@@ -30,7 +30,9 @@
     }
   },
   "require": {
-    "oxid-esales/oxideshop-ce": "6.0 - 6.3"
+    "php": ">=5.6",
+    "oxid-esales/oxideshop-ce": "6.0 - 6.3",
+    "spipu/html2pdf": "^5.2"
   },
   "autoload": {
     "psr-4": {