diff --git a/.travis.yml b/.travis.yml
index dc863ce..47def81 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -6,13 +6,14 @@ php:
   - 7.4
 
 env:
-  - SYMFONY_VERSION="2.1"
-  - SYMFONY_VERSION="3.0"
+  - SYMFONY_VERSION="3.4"
+  - SYMFONY_VERSION="4.0"
+  - SYMFONY_VERSION="4.4"
 
 before_script:
   - composer self-update
   - composer --version
   - composer require symfony/framework-bundle:${SYMFONY_VERSION} --no-update
-  - composer install -n --dev --prefer-source
+  - composer install -n --prefer-source
 
 script: phpunit --configuration phpunit.xml.dist
diff --git a/composer.json b/composer.json
index 396ff9b..72e84c0 100644
--- a/composer.json
+++ b/composer.json
@@ -2,8 +2,9 @@
     "name": "xola/reportwriter-bundle",
     "description": "A generic report writer",
     "require": {
+        "ext-json": "*",
         "php": ">=7.1",
-        "symfony/framework-bundle": ">=2.1 <4.0",
+        "symfony/framework-bundle": ">=2.1",
         "psr/log": "~1.0",
         "phpoffice/phpspreadsheet": "^1.3"
     },
diff --git a/src/Resources/config/services.yml b/src/Resources/config/services.yml
index 246e7af..7a111e0 100644
--- a/src/Resources/config/services.yml
+++ b/src/Resources/config/services.yml
@@ -11,7 +11,7 @@ services:
               - { name: monolog.logger, channel: csvwriter }
 
     excelwriter:
-        class: %excelwriter.service.class%
+        class: "%excelwriter.service.class%"
         arguments: [ "@logger", "@phpexcel" ]
         tags:
               - { name: monolog.logger, channel: excelwriter }
diff --git a/src/Service/ExcelWriter.php b/src/Service/ExcelWriter.php
index 22c3302..29ba511 100644
--- a/src/Service/ExcelWriter.php
+++ b/src/Service/ExcelWriter.php
@@ -376,4 +376,9 @@ private function incrementColumn($str, $count = 1)
 
         return $str;
     }
+
+    public function getCurrentRow(): int
+    {
+        return $this->currentRow;
+    }
 }
diff --git a/test/Service/ExcelWriterTest.php b/test/Service/ExcelWriterTest.php
index fe100ec..f395b41 100644
--- a/test/Service/ExcelWriterTest.php
+++ b/test/Service/ExcelWriterTest.php
@@ -60,9 +60,7 @@ public function testShouldSetCurrentWorksheet()
     {
         $index = 0;
         $title = 'Hello World';
-
-        // Setup all the mocks
-        $worksheetMock = $this->getMockBuilder('\PhpOffice\PhpSpreadsheet\Worksheet\Worksheet')->disableOriginalConstructor()->getMock();
+        $worksheetMock = $this->getMockBuilder(Worksheet::class)->disableOriginalConstructor()->getMock();
         $worksheetMock->expects($this->once())->method('setTitle')->with($title);
         $this->spreadsheet->expects($this->once())->method('getActiveSheet')->willReturn($worksheetMock);
         $this->spreadsheet->expects($this->once())->method('createSheet')->with($index);
@@ -71,7 +69,7 @@ public function testShouldSetCurrentWorksheet()
         $service = $this->buildService();
 
         $service->setWorksheet($index, $title);
-        $this->assertAttributeEquals(1, 'currentRow', $service, 'Row should be reset to 1 when switching active sheets');
+        $this->assertEquals(1, $service->getCurrentRow(), 'Row should be reset to 1 when switching active sheets');
     }
 
     public function testShouldWriteSingleRowHeaders()