diff --git a/composer.json b/composer.json
index 0786e69..f337ee4 100644
--- a/composer.json
+++ b/composer.json
@@ -17,16 +17,15 @@
     ],
     "require": {
         "php": ">=7.1",
-        "symfony/framework-bundle": "~3.4|~4.0",
         "twig/twig": "~2.0",
-        "phpoffice/phpspreadsheet": "~1.7.0"
+        "phpoffice/phpspreadsheet": "1.17.*"
     },
     "require-dev": {
-        "symfony/symfony": "~3.4|~4.0",
-        "sensio/framework-extra-bundle": "~3.0|~4.0",
-        "symfony/phpunit-bridge": "^4.0",
+        "symfony/symfony": "~3.4|~4.0|5.1.*|5.2.*",
+        "sensio/framework-extra-bundle": "~3.0|~4.0|5.1.*|5.2.*",
+        "symfony/phpunit-bridge": "^4.0|5.2.*",
         "phpunit/phpunit": "^7.5",
-        "mpdf/mpdf": "~7.0"
+        "mpdf/mpdf": "~8.0"
     },
     "suggest": {
         "mpdf/mpdf": "Add support for PDF rendering, requires ~7.0"
diff --git a/tests/Functional/BaseFunctionalTest.php b/tests/Functional/BaseFunctionalTest.php
index a06b9dc..534b520 100644
--- a/tests/Functional/BaseFunctionalTest.php
+++ b/tests/Functional/BaseFunctionalTest.php
@@ -108,7 +108,7 @@ protected function getDocument(string $routeName, array $routeParameters = [], s
      *
      * @return Response
      */
-    protected function getResponse(string $routeName, array $routeParameters = []): Response
+    protected static function getResponse(string $routeName, array $routeParameters = []): Response
     {
         /**
          * @var Router $router
diff --git a/tests/Twig/CsvOdsXlsXlsxErrorTwigTest.php b/tests/Twig/CsvOdsXlsXlsxErrorTwigTest.php
index 13411eb..0d8cf3c 100644
--- a/tests/Twig/CsvOdsXlsXlsxErrorTwigTest.php
+++ b/tests/Twig/CsvOdsXlsXlsxErrorTwigTest.php
@@ -74,7 +74,7 @@ public function testDocumentErrorTextBefore($format)
     public function testStartCellIndexError($format)
     {
         $this->expectException(\TypeError::class);
-        $this->expectExceptionMessage('Argument 1 passed to MewesK\TwigSpreadsheetBundle\Wrapper\PhpSpreadsheetWrapper::startCell() must be of the type integer');
+        $this->expectExceptionMessage('Argument 1 passed to MewesK\TwigSpreadsheetBundle\Wrapper\PhpSpreadsheetWrapper::startCell() must be of the type int or null');
 
         $this->getDocument('cellIndexError', $format);
     }
@@ -89,7 +89,7 @@ public function testStartCellIndexError($format)
     public function testStartRowIndexError($format)
     {
         $this->expectException(\TypeError::class);
-        $this->expectExceptionMessage('Argument 1 passed to MewesK\TwigSpreadsheetBundle\Wrapper\PhpSpreadsheetWrapper::startRow() must be of the type integer');
+        $this->expectExceptionMessage('Argument 1 passed to MewesK\TwigSpreadsheetBundle\Wrapper\PhpSpreadsheetWrapper::startRow() must be of the type int or null');
 
         $this->getDocument('rowIndexError', $format);
     }