diff --git a/src/Constants.php b/src/Constants.php
index 8d22452c..a7b56569 100644
--- a/src/Constants.php
+++ b/src/Constants.php
@@ -17,11 +17,11 @@ class Constants
     /**
      * The current release version
      */
-    public const VERSION = '1.8';
+    public const VERSION = '1.9';
     /**
      * The current release status, either "stable" or "dev"
      */
-    public const STATUS = 'stable';
+    public const STATUS = 'dev';
     /**
      * The software name
      */
diff --git a/src/Form/Type/LanguageType.php b/src/Form/Type/LanguageType.php
index c3877bf9..1225dc5b 100644
--- a/src/Form/Type/LanguageType.php
+++ b/src/Form/Type/LanguageType.php
@@ -48,7 +48,8 @@ class LanguageType extends AbstractType
         }
 
         $resolver->setDefaults([
-            'choices' => $choices
+            'choices' => $choices,
+            'label' => 'label.language',
         ]);
     }
 
diff --git a/src/Invoice/NumberGenerator/ConfigurableNumberGenerator.php b/src/Invoice/NumberGenerator/ConfigurableNumberGenerator.php
index 15eec569..73163231 100644
--- a/src/Invoice/NumberGenerator/ConfigurableNumberGenerator.php
+++ b/src/Invoice/NumberGenerator/ConfigurableNumberGenerator.php
@@ -75,31 +75,31 @@ final class ConfigurableNumberGenerator implements NumberGeneratorInterface
 
             switch ($tmp) {
                 case 'Y':
-                    $partialResult = date('Y', $timestamp);
+                    $partialResult = $invoiceDate->format('Y');
                     break;
 
                 case 'y':
-                    $partialResult = date('y', $timestamp);
+                    $partialResult = $invoiceDate->format('y');
                     break;
 
                 case 'M':
-                    $partialResult = date('m', $timestamp);
+                    $partialResult = $invoiceDate->format('m');
                     break;
 
                 case 'm':
-                    $partialResult = date('n', $timestamp);
+                    $partialResult = $invoiceDate->format('n');
                     break;
 
                 case 'D':
-                    $partialResult = date('d', $timestamp);
+                    $partialResult = $invoiceDate->format('d');
                     break;
 
                 case 'd':
-                    $partialResult = date('j', $timestamp);
+                    $partialResult = $invoiceDate->format('j');
                     break;
 
                 case 'date':
-                    $partialResult = date('ymd', $timestamp);
+                    $partialResult = $invoiceDate->format('ymd');
                     break;
 
                 case 'c':
diff --git a/src/Invoice/Renderer/JsonRenderer.php b/src/Invoice/Renderer/JsonRenderer.php
new file mode 100644
index 00000000..01181abf
--- /dev/null
+++ b/src/Invoice/Renderer/JsonRenderer.php
@@ -0,0 +1,53 @@
+<?php
+
+/*
+ * This file is part of the Kimai time-tracking app.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace App\Invoice\Renderer;
+
+use App\Entity\InvoiceDocument;
+use App\Invoice\InvoiceFilename;
+use App\Invoice\InvoiceModel;
+use App\Invoice\RendererInterface;
+use Symfony\Component\HttpFoundation\Response;
+use Symfony\Component\HttpFoundation\ResponseHeaderBag;
+use Twig\Environment;
+
+final class JsonRenderer implements RendererInterface
+{
+    /**
+     * @var Environment
+     */
+    private $twig;
+
+    public function __construct(Environment $twig)
+    {
+        $this->twig = $twig;
+    }
+
+    public function supports(InvoiceDocument $document): bool
+    {
+        return stripos($document->getFilename(), '.json.twig') !== false;
+    }
+
+    public function render(InvoiceDocument $document, InvoiceModel $model): Response
+    {
+        $content = $this->twig->render('@invoice/' . basename($document->getFilename()), [
+            'model' => $model
+        ]);
+        $filename = (string) new InvoiceFilename($model);
+
+        $response = new Response($content);
+
+        $disposition = $response->headers->makeDisposition(ResponseHeaderBag::DISPOSITION_ATTACHMENT, $filename . '.json');
+
+        $response->headers->set('Content-Type', 'application/json');
+        $response->headers->set('Content-Disposition', $disposition);
+
+        return $response;
+    }
+}
diff --git a/src/Invoice/Renderer/TextRenderer.php b/src/Invoice/Renderer/TextRenderer.php
new file mode 100644
index 00000000..e148f086
--- /dev/null
+++ b/src/Invoice/Renderer/TextRenderer.php
@@ -0,0 +1,53 @@
+<?php
+
+/*
+ * This file is part of the Kimai time-tracking app.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace App\Invoice\Renderer;
+
+use App\Entity\InvoiceDocument;
+use App\Invoice\InvoiceFilename;
+use App\Invoice\InvoiceModel;
+use App\Invoice\RendererInterface;
+use Symfony\Component\HttpFoundation\Response;
+use Symfony\Component\HttpFoundation\ResponseHeaderBag;
+use Twig\Environment;
+
+final class TextRenderer implements RendererInterface
+{
+    /**
+     * @var Environment
+     */
+    private $twig;
+
+    public function __construct(Environment $twig)
+    {
+        $this->twig = $twig;
+    }
+
+    public function supports(InvoiceDocument $document): bool
+    {
+        return stripos($document->getFilename(), '.txt.twig') !== false;
+    }
+
+    public function render(InvoiceDocument $document, InvoiceModel $model): Response
+    {
+        $content = $this->twig->render('@invoice/' . basename($document->getFilename()), [
+            'model' => $model
+        ]);
+        $filename = (string) new InvoiceFilename($model);
+
+        $response = new Response($content);
+
+        $disposition = $response->headers->makeDisposition(ResponseHeaderBag::DISPOSITION_ATTACHMENT, $filename . '.txt');
+
+        $response->headers->set('Content-Type', 'text/plain');
+        $response->headers->set('Content-Disposition', $disposition);
+
+        return $response;
+    }
+}
diff --git a/src/Invoice/Renderer/XmlRenderer.php b/src/Invoice/Renderer/XmlRenderer.php
new file mode 100644
index 00000000..6c1fb935
--- /dev/null
+++ b/src/Invoice/Renderer/XmlRenderer.php
@@ -0,0 +1,53 @@
+<?php
+
+/*
+ * This file is part of the Kimai time-tracking app.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace App\Invoice\Renderer;
+
+use App\Entity\InvoiceDocument;
+use App\Invoice\InvoiceFilename;
+use App\Invoice\InvoiceModel;
+use App\Invoice\RendererInterface;
+use Symfony\Component\HttpFoundation\Response;
+use Symfony\Component\HttpFoundation\ResponseHeaderBag;
+use Twig\Environment;
+
+final class XmlRenderer implements RendererInterface
+{
+    /**
+     * @var Environment
+     */
+    private $twig;
+
+    public function __construct(Environment $twig)
+    {
+        $this->twig = $twig;
+    }
+
+    public function supports(InvoiceDocument $document): bool
+    {
+        return stripos($document->getFilename(), '.xml.twig') !== false;
+    }
+
+    public function render(InvoiceDocument $document, InvoiceModel $model): Response
+    {
+        $content = $this->twig->render('@invoice/' . basename($document->getFilename()), [
+            'model' => $model
+        ]);
+        $filename = (string) new InvoiceFilename($model);
+
+        $response = new Response($content);
+
+        $disposition = $response->headers->makeDisposition(ResponseHeaderBag::DISPOSITION_ATTACHMENT, $filename . '.xml');
+
+        $response->headers->set('Content-Type', 'application/xml');
+        $response->headers->set('Content-Disposition', $disposition);
+
+        return $response;
+    }
+}
diff --git a/src/Twig/Extensions.php b/src/Twig/Extensions.php
index 07d39fa4..080e9f7c 100644
--- a/src/Twig/Extensions.php
+++ b/src/Twig/Extensions.php
@@ -71,6 +71,7 @@ class Extensions extends AbstractExtension
             new TwigFilter('language', [$this, 'language']),
             new TwigFilter('amount', [$this, 'amount']),
             new TwigFilter('docu_link', [$this, 'documentationLink']),
+            new TwigFilter('multiline_indent', [$this, 'multilineIndent']),
         ];
     }
 
@@ -98,6 +99,24 @@ class Extensions extends AbstractExtension
         return get_class($object);
     }
 
+    public function multilineIndent(?string $string, string $indent): string
+    {
+        if (null === $string || '' === $string) {
+            return '';
+        }
+
+        $parts = explode("\r\n", $string);
+        if (count($parts) === 1) {
+            $parts = explode("\n", $string);
+        }
+
+        $parts = array_map(function ($part) use ($indent) {
+            return $indent . $part;
+        }, $parts);
+
+        return implode("\n", $parts);
+    }
+
     /**
      * Transforms seconds into a duration string.
      *
diff --git a/templates/doctor/index.html.twig b/templates/doctor/index.html.twig
index fa5bec56..056685a0 100644
--- a/templates/doctor/index.html.twig
+++ b/templates/doctor/index.html.twig
@@ -87,6 +87,8 @@
                 {%- set logLineClass = '' -%}
                 {%- if '.CRITICAL' in logLine -%}
                     {%- set logLineClass = 'text-danger text-bold' -%}
+                {%- elseif '.WARNING' in logLine -%}
+                    {%- set logLineClass = 'text-warning text-bold' -%}
                 {%- elseif '.ERROR' in logLine -%}
                     {%- set logLineClass = 'text-warning text-bold' -%}
                 {%- elseif '.DEBUG' in logLine -%}
diff --git a/templates/invoice/renderer/javascript.json.twig b/templates/invoice/renderer/javascript.json.twig
new file mode 100644
index 00000000..6cf6b5df
--- /dev/null
+++ b/templates/invoice/renderer/javascript.json.twig
@@ -0,0 +1,7 @@
+{% set json = model.toArray %}
+{% set items = [] %}
+{% for entry in model.calculator.entries %}
+{% set items = items|merge([model.itemToArray(entry)]) %}
+{% endfor %}
+{% set json = json|merge({'items': items}) %}
+{{ json|json_encode|raw}}
\ No newline at end of file
diff --git a/templates/invoice/renderer/text.txt.twig b/templates/invoice/renderer/text.txt.twig
new file mode 100644
index 00000000..7e8b3077
--- /dev/null
+++ b/templates/invoice/renderer/text.txt.twig
@@ -0,0 +1,19 @@
+{% for key, value in model.toArray %}
+{{ key }}:
+{% if value is not empty %}
+{{ value|multiline_indent('    ') }}
+{% endif %}
+
+{% endfor %}
+{% for entry in model.calculator.entries %}
+---
+
+{% set items = model.itemToArray(entry) %}
+{% for key, value in items %}
+{{ key }}:
+{% if value is not empty %}
+{{ value|multiline_indent('    ') }}
+{% endif %}
+
+{% endfor %}
+{% endfor %}
diff --git a/templates/invoice/renderer/xml.xml.twig b/templates/invoice/renderer/xml.xml.twig
new file mode 100644
index 00000000..ed865626
--- /dev/null
+++ b/templates/invoice/renderer/xml.xml.twig
@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<kimai version="{{ constant('App\\Constants::VERSION') }}">
+{% for key, value in model.toArray %}
+    <{{ key }}{% if value is empty %}/>{% else %}>{{ value|escape }}</{{ key }}>{% endif %}
+
+{% endfor %}
+    <items>
+        {%- for entry in model.calculator.entries %}
+
+        <item>
+{% for key, value in model.itemToArray(entry) %}
+            <{{ key }}{% if value is empty %}/>{% else %}>{{ value|escape }}</{{ key }}>{% endif %}
+
+{% endfor %}
+        </item>
+        {%- endfor %}
+
+    </items>
+</kimai>
\ No newline at end of file
diff --git a/tests/Command/InvoiceCreateCommandTest.php b/tests/Command/InvoiceCreateCommandTest.php
index 9ad0da08..e7343bda 100644
--- a/tests/Command/InvoiceCreateCommandTest.php
+++ b/tests/Command/InvoiceCreateCommandTest.php
@@ -77,20 +77,20 @@ class InvoiceCreateCommandTest extends KernelTestCase
     }
 
     /**
-        'user'
-        'start'
-        'end'
-        'timezone'
-        'customer'
-        'template'
-        'search'
-        'exported'
-        'by-customer'
-        'by-project'
-        'set-exported'
-        'template-meta'
-     * @param $user
-     * @param array $params
+     * Allowed option: user
+     * Allowed option: start
+     * Allowed option: end
+     * Allowed option: timezone
+     * Allowed option: customer
+     * Allowed option: template
+     * Allowed option: search
+     * Allowed option: exported
+     * Allowed option: by-customer
+     * Allowed option: by-project
+     * Allowed option: set-exported
+     * Allowed option: template-meta
+     *
+     * @param array $options
      * @return CommandTester
      */
     protected function createInvoice(array $options = [])
diff --git a/tests/Invoice/NumberGenerator/ConfigurableNumberGeneratorTest.php b/tests/Invoice/NumberGenerator/ConfigurableNumberGeneratorTest.php
index 2d1604ce..2483513c 100644
--- a/tests/Invoice/NumberGenerator/ConfigurableNumberGeneratorTest.php
+++ b/tests/Invoice/NumberGenerator/ConfigurableNumberGeneratorTest.php
@@ -51,47 +51,47 @@ class ConfigurableNumberGeneratorTest extends TestCase
 
     public function getTestData()
     {
-        $timestamp = time();
+        $invoiceDate = new \DateTime();
 
         return [
             // simple tests for single calls
-            ['{date}', date('ymd'), $timestamp],
-            ['{Y}', date('Y'), $timestamp],
-            ['{y}', date('y'), $timestamp],
-            ['{M}', date('m'), $timestamp],
-            ['{m}', date('n'), $timestamp],
-            ['{D}', date('d'), $timestamp],
-            ['{d}', date('j'), $timestamp],
-            ['{c}', '2', $timestamp],
-            ['{cy}', '2', $timestamp],
-            ['{cm}', '2', $timestamp],
-            ['{cd}', '2', $timestamp],
+            ['{date}', $invoiceDate->format('ymd'), $invoiceDate],
+            ['{Y}', $invoiceDate->format('Y'), $invoiceDate],
+            ['{y}', $invoiceDate->format('y'), $invoiceDate],
+            ['{M}', $invoiceDate->format('m'), $invoiceDate],
+            ['{m}', $invoiceDate->format('n'), $invoiceDate],
+            ['{D}', $invoiceDate->format('d'), $invoiceDate],
+            ['{d}', $invoiceDate->format('j'), $invoiceDate],
+            ['{c}', '2', $invoiceDate],
+            ['{cy}', '2', $invoiceDate],
+            ['{cm}', '2', $invoiceDate],
+            ['{cd}', '2', $invoiceDate],
             // number formatting (not testing the lower case versions, as the tests might break depending on the date)
-            ['{date,10}', '0000' . date('ymd'), $timestamp],
-            ['{Y,6}', '00' . date('Y'), $timestamp],
-            ['{M,3}', '0' . date('m'), $timestamp],
-            ['{D,3}', '0' . date('d'), $timestamp],
-            ['{c,2}', '02', $timestamp],
-            ['{cy,2}', '02', $timestamp],
-            ['{cm,2}', '02', $timestamp],
-            ['{cd,2}', '02', $timestamp],
+            ['{date,10}', '0000' . $invoiceDate->format('ymd'), $invoiceDate],
+            ['{Y,6}', '00' . $invoiceDate->format('Y'), $invoiceDate],
+            ['{M,3}', '0' . $invoiceDate->format('m'), $invoiceDate],
+            ['{D,3}', '0' . $invoiceDate->format('d'), $invoiceDate],
+            ['{c,2}', '02', $invoiceDate],
+            ['{cy,2}', '02', $invoiceDate],
+            ['{cm,2}', '02', $invoiceDate],
+            ['{cd,2}', '02', $invoiceDate],
             // mixing identifiers
-            ['{Y}{cy}', date('Y') . '2', $timestamp],
-            ['{Y}{cy}{m}', date('Y') . '2' . date('n'), $timestamp],
-            ['{Y}-{cy}/{m}', date('Y') . '-2/' . date('n'), $timestamp],
-            ['{Y}-{cy}/{m}', date('Y') . '-2/' . date('n'), $timestamp],
-            ['{Y,5}/{cy,5}', '0' . date('Y') . '/00002', $timestamp],
+            ['{Y}{cy}', $invoiceDate->format('Y') . '2', $invoiceDate],
+            ['{Y}{cy}{m}', $invoiceDate->format('Y') . '2' . $invoiceDate->format('n'), $invoiceDate],
+            ['{Y}-{cy}/{m}', $invoiceDate->format('Y') . '-2/' . $invoiceDate->format('n'), $invoiceDate],
+            ['{Y}-{cy}/{m}', $invoiceDate->format('Y') . '-2/' . $invoiceDate->format('n'), $invoiceDate],
+            ['{Y,5}/{cy,5}', '0' . $invoiceDate->format('Y') . '/00002', $invoiceDate],
         ];
     }
 
     /**
      * @dataProvider getTestData
      */
-    public function testGetInvoiceNumber(string $format, string $expectedInvoiceNumber, int $timestamp)
+    public function testGetInvoiceNumber(string $format, string $expectedInvoiceNumber, \DateTime $invoiceDate)
     {
         $sut = $this->getSut($format);
         $model = new InvoiceModel(new DebugFormatter());
-        $model->setInvoiceDate((new \DateTime())->setTimestamp($timestamp));
+        $model->setInvoiceDate($invoiceDate);
         $sut->setModel($model);
 
         $this->assertEquals($expectedInvoiceNumber, $sut->getInvoiceNumber());
diff --git a/tests/Invoice/Renderer/JsonRendererTest.php b/tests/Invoice/Renderer/JsonRendererTest.php
new file mode 100644
index 00000000..d91f37ac
--- /dev/null
+++ b/tests/Invoice/Renderer/JsonRendererTest.php
@@ -0,0 +1,77 @@
+<?php
+
+/*
+ * This file is part of the Kimai time-tracking app.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace App\Tests\Invoice\Renderer;
+
+use App\Invoice\Renderer\JsonRenderer;
+use Symfony\Bundle\FrameworkBundle\Test\KernelTestCase;
+use Symfony\Component\HttpFoundation\Request;
+use Twig\Environment;
+use Twig\Loader\FilesystemLoader;
+
+/**
+ * @covers \App\Invoice\Renderer\JsonRenderer
+ * @group integration
+ */
+class JsonRendererTest extends KernelTestCase
+{
+    use RendererTestTrait;
+
+    public function testSupports()
+    {
+        $loader = new FilesystemLoader();
+        $env = new Environment($loader);
+        $sut = new JsonRenderer($env);
+
+        $this->assertFalse($sut->supports($this->getInvoiceDocument('default.html.twig')));
+        $this->assertFalse($sut->supports($this->getInvoiceDocument('freelancer.html.twig')));
+        $this->assertFalse($sut->supports($this->getInvoiceDocument('timesheet.html.twig')));
+        $this->assertFalse($sut->supports($this->getInvoiceDocument('foo.html.twig')));
+        $this->assertFalse($sut->supports($this->getInvoiceDocument('company.docx')));
+        $this->assertFalse($sut->supports($this->getInvoiceDocument('export.csv')));
+        $this->assertFalse($sut->supports($this->getInvoiceDocument('spreadsheet.xlsx')));
+        $this->assertFalse($sut->supports($this->getInvoiceDocument('open-spreadsheet.ods')));
+        $this->assertFalse($sut->supports($this->getInvoiceDocument('text.txt.twig')));
+        $this->assertTrue($sut->supports($this->getInvoiceDocument('javascript.json.twig')));
+        $this->assertFalse($sut->supports($this->getInvoiceDocument('xml.xml.twig')));
+    }
+
+    public function testRender()
+    {
+        $kernel = self::bootKernel();
+        /** @var Environment $twig */
+        $twig = $kernel->getContainer()->get('twig');
+        $stack = $kernel->getContainer()->get('request_stack');
+        $request = new Request();
+        $request->setLocale('en');
+        $stack->push($request);
+
+        /** @var FilesystemLoader $loader */
+        $loader = $twig->getLoader();
+        $loader->addPath($this->getInvoiceTemplatePath(), 'invoice');
+
+        $sut = new JsonRenderer($twig);
+
+        $model = $this->getInvoiceModel();
+
+        $document = $this->getInvoiceDocument('javascript.json.twig');
+        $response = $sut->render($document, $model);
+
+        self::assertEquals('application/json', $response->headers->get('Content-Type'));
+        $content = $response->getContent();
+        $json = json_decode($content, true);
+
+        $expected = $model->toArray();
+        $expected['items'] = [];
+        foreach ($model->getCalculator()->getEntries() as $entry) {
+            $expected['items'][] = $model->itemToArray($entry);
+        }
+        self::assertEquals($expected, $json);
+    }
+}
diff --git a/tests/Invoice/Renderer/TextRendererTest.php b/tests/Invoice/Renderer/TextRendererTest.php
new file mode 100644
index 00000000..3f281c3c
--- /dev/null
+++ b/tests/Invoice/Renderer/TextRendererTest.php
@@ -0,0 +1,79 @@
+<?php
+
+/*
+ * This file is part of the Kimai time-tracking app.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace App\Tests\Invoice\Renderer;
+
+use App\Invoice\Renderer\TextRenderer;
+use Symfony\Bundle\FrameworkBundle\Test\KernelTestCase;
+use Symfony\Component\HttpFoundation\Request;
+use Twig\Environment;
+use Twig\Loader\FilesystemLoader;
+
+/**
+ * @covers \App\Invoice\Renderer\TextRenderer
+ * @group integration
+ */
+class TextRendererTest extends KernelTestCase
+{
+    use RendererTestTrait;
+
+    public function testSupports()
+    {
+        $loader = new FilesystemLoader();
+        $env = new Environment($loader);
+        $sut = new TextRenderer($env);
+
+        $this->assertFalse($sut->supports($this->getInvoiceDocument('default.html.twig')));
+        $this->assertFalse($sut->supports($this->getInvoiceDocument('freelancer.html.twig')));
+        $this->assertFalse($sut->supports($this->getInvoiceDocument('timesheet.html.twig')));
+        $this->assertFalse($sut->supports($this->getInvoiceDocument('foo.html.twig')));
+        $this->assertFalse($sut->supports($this->getInvoiceDocument('company.docx')));
+        $this->assertFalse($sut->supports($this->getInvoiceDocument('export.csv')));
+        $this->assertFalse($sut->supports($this->getInvoiceDocument('spreadsheet.xlsx')));
+        $this->assertFalse($sut->supports($this->getInvoiceDocument('open-spreadsheet.ods')));
+        $this->assertTrue($sut->supports($this->getInvoiceDocument('text.txt.twig')));
+        $this->assertFalse($sut->supports($this->getInvoiceDocument('javascript.json.twig')));
+        $this->assertFalse($sut->supports($this->getInvoiceDocument('xml.xml.twig')));
+    }
+
+    public function testRender()
+    {
+        $kernel = self::bootKernel();
+        /** @var Environment $twig */
+        $twig = $kernel->getContainer()->get('twig');
+        $stack = $kernel->getContainer()->get('request_stack');
+        $request = new Request();
+        $request->setLocale('en');
+        $stack->push($request);
+
+        /** @var FilesystemLoader $loader */
+        $loader = $twig->getLoader();
+        $loader->addPath($this->getInvoiceTemplatePath(), 'invoice');
+
+        $sut = new TextRenderer($twig);
+
+        $model = $this->getInvoiceModel();
+
+        $document = $this->getInvoiceDocument('text.txt.twig');
+        $response = $sut->render($document, $model);
+
+        self::assertEquals('text/plain', $response->headers->get('Content-Type'));
+
+        $content = $response->getContent();
+
+        foreach ($model->toArray() as $key => $value) {
+            if (null === $value || '' === $value) {
+                self::assertStringContainsString(sprintf("%s:\n\n", $key), $content);
+            } else {
+                self::assertStringContainsString(sprintf("%s:\n    %s", $key, explode("\n", $value)[0]), $content);
+            }
+        }
+        self::assertEquals(count($model->getCalculator()->getEntries()), substr_count($content, PHP_EOL . '---' . PHP_EOL));
+    }
+}
diff --git a/tests/Invoice/Renderer/XmlRendererTest.php b/tests/Invoice/Renderer/XmlRendererTest.php
new file mode 100644
index 00000000..2cf531e0
--- /dev/null
+++ b/tests/Invoice/Renderer/XmlRendererTest.php
@@ -0,0 +1,83 @@
+<?php
+
+/*
+ * This file is part of the Kimai time-tracking app.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace App\Tests\Invoice\Renderer;
+
+use App\Invoice\Renderer\XmlRenderer;
+use Symfony\Bundle\FrameworkBundle\Test\KernelTestCase;
+use Symfony\Component\HttpFoundation\Request;
+use Twig\Environment;
+use Twig\Loader\FilesystemLoader;
+
+/**
+ * @covers \App\Invoice\Renderer\XmlRenderer
+ * @group integration
+ */
+class XmlRendererTest extends KernelTestCase
+{
+    use RendererTestTrait;
+
+    public function testSupports()
+    {
+        $loader = new FilesystemLoader();
+        $env = new Environment($loader);
+        $sut = new XmlRenderer($env);
+
+        $this->assertFalse($sut->supports($this->getInvoiceDocument('default.html.twig')));
+        $this->assertFalse($sut->supports($this->getInvoiceDocument('freelancer.html.twig')));
+        $this->assertFalse($sut->supports($this->getInvoiceDocument('timesheet.html.twig')));
+        $this->assertFalse($sut->supports($this->getInvoiceDocument('javascript.json.twig')));
+        $this->assertFalse($sut->supports($this->getInvoiceDocument('foo.html.twig')));
+        $this->assertFalse($sut->supports($this->getInvoiceDocument('company.docx')));
+        $this->assertFalse($sut->supports($this->getInvoiceDocument('export.csv')));
+        $this->assertFalse($sut->supports($this->getInvoiceDocument('spreadsheet.xlsx')));
+        $this->assertFalse($sut->supports($this->getInvoiceDocument('open-spreadsheet.ods')));
+        $this->assertFalse($sut->supports($this->getInvoiceDocument('text.txt.twig')));
+        $this->assertFalse($sut->supports($this->getInvoiceDocument('javascript.json.twig')));
+        $this->assertTrue($sut->supports($this->getInvoiceDocument('xml.xml.twig')));
+    }
+
+    public function testRender()
+    {
+        $kernel = self::bootKernel();
+        /** @var Environment $twig */
+        $twig = $kernel->getContainer()->get('twig');
+        $stack = $kernel->getContainer()->get('request_stack');
+        $request = new Request();
+        $request->setLocale('en');
+        $stack->push($request);
+
+        /** @var FilesystemLoader $loader */
+        $loader = $twig->getLoader();
+        $loader->addPath($this->getInvoiceTemplatePath(), 'invoice');
+
+        $sut = new XmlRenderer($twig);
+
+        $model = $this->getInvoiceModel();
+
+        $document = $this->getInvoiceDocument('xml.xml.twig');
+        $response = $sut->render($document, $model);
+
+        self::assertEquals('application/xml', $response->headers->get('Content-Type'));
+
+        $content = $response->getContent();
+        $xml = new \SimpleXMLElement($content);
+
+        $expected = $model->toArray();
+
+        foreach ($xml as $element) {
+            $name = $element->getName();
+            if ($name === 'items') {
+                continue;
+            }
+            self::assertEquals((string) $expected[$name], (string) $element);
+        }
+        self::assertEquals(count($model->getCalculator()->getEntries()), count($xml->items->item));
+    }
+}
diff --git a/tests/KernelTestTrait.php b/tests/KernelTestTrait.php
index 1e252c9c..8eb4b6ee 100644
--- a/tests/KernelTestTrait.php
+++ b/tests/KernelTestTrait.php
@@ -24,7 +24,7 @@ use Symfony\Component\HttpKernel\HttpKernelBrowser;
 trait KernelTestTrait
 {
     /**
-     * @param $client HttpKernelBrowser|EntityManager|KernelTestCase
+     * @param HttpKernelBrowser|EntityManager|KernelTestCase $client
      * @param Fixture $fixture
      */
     protected function importFixture($client, Fixture $fixture)
diff --git a/tests/Repository/InvoiceDocumentRepositoryTest.php b/tests/Repository/InvoiceDocumentRepositoryTest.php
index 1f9cc36f..db0fffc9 100644
--- a/tests/Repository/InvoiceDocumentRepositoryTest.php
+++ b/tests/Repository/InvoiceDocumentRepositoryTest.php
@@ -27,6 +27,9 @@ class InvoiceDocumentRepositoryTest extends TestCase
         'default.html.twig',
         'freelancer.html.twig',
         'timesheet.html.twig',
+        'text.txt.twig',
+        'javascript.json.twig',
+        'xml.xml.twig',
     ];
 
     public function testWithEmptyDirectory()
diff --git a/tests/Twig/ExtensionsTest.php b/tests/Twig/ExtensionsTest.php
index 96dffe69..92a1be91 100644
--- a/tests/Twig/ExtensionsTest.php
+++ b/tests/Twig/ExtensionsTest.php
@@ -50,7 +50,7 @@ class ExtensionsTest extends TestCase
 
     public function testGetFilters()
     {
-        $filters = ['duration', 'duration_decimal', 'money', 'currency', 'country', 'language', 'amount', 'docu_link'];
+        $filters = ['duration', 'duration_decimal', 'money', 'currency', 'country', 'language', 'amount', 'docu_link', 'multiline_indent'];
         $sut = $this->getSut($this->localeDe);
         $twigFilters = $sut->getFilters();
         $this->assertCount(count($filters), $twigFilters);
@@ -305,4 +305,43 @@ class ExtensionsTest extends TestCase
         $this->assertNull($sut->getClassName(null));
         $this->assertEquals('App\Entity\User', $sut->getClassName(new User()));
     }
+
+    public function getMultilineTestData()
+    {
+        return [
+            ['    ', null, ['']],
+            ['    ', '', ['']],
+            ['    ', 0, ['    0']],
+            ['    ', 'sdfsdf
+sdfsdf
+
+ aksljdfh laksjd hflka sjhdf lakjhsdflak jsdfh
+dfsdfsdfsdfsdf',
+                ['    sdfsdf', '    sdfsdf', '    ', '     aksljdfh laksjd hflka sjhdf lakjhsdflak jsdfh', '    dfsdfsdfsdfsdf']
+            ],
+            ['###', 'sdfsdf' . PHP_EOL .
+'sdfsdf' . PHP_EOL .
+'' . PHP_EOL .
+' aksljdfh laksjd hflka sjhdf lakjhsdflak jsdfh' . PHP_EOL .
+'dfsdfsdfsdfsdf',
+                ['###sdfsdf', '###sdfsdf', '###', '### aksljdfh laksjd hflka sjhdf lakjhsdflak jsdfh', '###dfsdfsdfsdfsdf']
+            ],
+            ['  ', 'sdfsdf' . "\r\n" .
+'sdfsdf' . "\r\n" .
+'' . "\r\n" .
+' aksljdfh laksjd hflka sjhdf lakjhsdflak jsdfh' . "\r\n" .
+'dfsdfsdfsdfsdf',
+                ['  sdfsdf', '  sdfsdf', '  ', '   aksljdfh laksjd hflka sjhdf lakjhsdflak jsdfh', '  dfsdfsdfsdfsdf']
+            ],
+        ];
+    }
+
+    /**
+     * @dataProvider getMultilineTestData
+     */
+    public function testMultilineIndent($indent, $string, $expected)
+    {
+        $sut = $this->getSut($this->localeEn);
+        self::assertEquals(implode("\n", $expected), $sut->multilineIndent($string, $indent));
+    }
 }