diff --git a/composer.json b/composer.json
index bd936d472e..7442f7a666 100644
--- a/composer.json
+++ b/composer.json
@@ -11,7 +11,6 @@
   ],
   "require": {
     "php": ">=5.6",
-    "twig/twig": "1.*",
     "cerdic/css-tidy": "^1.6",
     "tburry/pquery": "^1.1.1",
     "j4mie/paris": "1.5.6",
diff --git a/composer.lock b/composer.lock
index ee50afd534..5d094e4f9a 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "81e44efee9f040a7e302f96ae2265d93",
+    "content-hash": "ace24c4002870bd939be3fc6625f9216",
     "packages": [
         {
             "name": "cerdic/css-tidy",
@@ -431,64 +431,6 @@
             },
             "time": "2018-07-09T16:02:27+00:00"
         },
-        {
-            "name": "symfony/polyfill-ctype",
-            "version": "v1.10.0",
-            "source": {
-                "type": "git",
-                "url": "https://github.com/symfony/polyfill-ctype.git",
-                "reference": "e3d826245268269cd66f8326bd8bc066687b4a19"
-            },
-            "dist": {
-                "type": "zip",
-                "url": "https://api.github.com/repos/symfony/polyfill-ctype/zipball/e3d826245268269cd66f8326bd8bc066687b4a19",
-                "reference": "e3d826245268269cd66f8326bd8bc066687b4a19",
-                "shasum": ""
-            },
-            "require": {
-                "php": ">=5.3.3"
-            },
-            "suggest": {
-                "ext-ctype": "For best performance"
-            },
-            "type": "library",
-            "extra": {
-                "branch-alias": {
-                    "dev-master": "1.9-dev"
-                }
-            },
-            "autoload": {
-                "psr-4": {
-                    "Symfony\\Polyfill\\Ctype\\": ""
-                },
-                "files": [
-                    "bootstrap.php"
-                ]
-            },
-            "notification-url": "https://packagist.org/downloads/",
-            "license": [
-                "MIT"
-            ],
-            "authors": [
-                {
-                    "name": "Symfony Community",
-                    "homepage": "https://symfony.com/contributors"
-                },
-                {
-                    "name": "Gert de Pagter",
-                    "email": "BackEndTea@gmail.com"
-                }
-            ],
-            "description": "Symfony polyfill for ctype functions",
-            "homepage": "https://symfony.com",
-            "keywords": [
-                "compatibility",
-                "ctype",
-                "polyfill",
-                "portable"
-            ],
-            "time": "2018-08-06T14:22:27+00:00"
-        },
         {
             "name": "symfony/polyfill-mbstring",
             "version": "v1.10.0",
@@ -718,72 +660,6 @@
                 "php"
             ],
             "time": "2016-01-14T20:55:00+00:00"
-        },
-        {
-            "name": "twig/twig",
-            "version": "v1.38.0",
-            "source": {
-                "type": "git",
-                "url": "https://github.com/twigphp/Twig.git",
-                "reference": "754b8dfc0026585eb8498ec4bf5ff240b6b34db7"
-            },
-            "dist": {
-                "type": "zip",
-                "url": "https://api.github.com/repos/twigphp/Twig/zipball/754b8dfc0026585eb8498ec4bf5ff240b6b34db7",
-                "reference": "754b8dfc0026585eb8498ec4bf5ff240b6b34db7",
-                "shasum": ""
-            },
-            "require": {
-                "php": ">=5.4.0",
-                "symfony/polyfill-ctype": "^1.8"
-            },
-            "require-dev": {
-                "psr/container": "^1.0",
-                "symfony/debug": "^2.7",
-                "symfony/phpunit-bridge": "^3.4.19|^4.1.8"
-            },
-            "type": "library",
-            "extra": {
-                "branch-alias": {
-                    "dev-master": "1.38-dev"
-                }
-            },
-            "autoload": {
-                "psr-0": {
-                    "Twig_": "lib/"
-                },
-                "psr-4": {
-                    "Twig\\": "src/"
-                }
-            },
-            "notification-url": "https://packagist.org/downloads/",
-            "license": [
-                "BSD-3-Clause"
-            ],
-            "authors": [
-                {
-                    "name": "Fabien Potencier",
-                    "email": "fabien@symfony.com",
-                    "homepage": "http://fabien.potencier.org",
-                    "role": "Lead Developer"
-                },
-                {
-                    "name": "Armin Ronacher",
-                    "email": "armin.ronacher@active-4.com",
-                    "role": "Project Founder"
-                },
-                {
-                    "name": "Twig Team",
-                    "homepage": "https://twig.symfony.com/contributors",
-                    "role": "Contributors"
-                }
-            ],
-            "description": "Twig, the flexible, fast, and secure template language for PHP",
-            "homepage": "https://twig.symfony.com",
-            "keywords": [
-                "templating"
-            ],
-            "time": "2019-03-12T12:42:04+00:00"
         }
     ],
     "packages-dev": [
@@ -6153,6 +6029,64 @@
             ],
             "time": "2018-11-11T11:18:13+00:00"
         },
+        {
+            "name": "symfony/polyfill-ctype",
+            "version": "v1.11.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/symfony/polyfill-ctype.git",
+                "reference": "82ebae02209c21113908c229e9883c419720738a"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/symfony/polyfill-ctype/zipball/82ebae02209c21113908c229e9883c419720738a",
+                "reference": "82ebae02209c21113908c229e9883c419720738a",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.3.3"
+            },
+            "suggest": {
+                "ext-ctype": "For best performance"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.11-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Symfony\\Polyfill\\Ctype\\": ""
+                },
+                "files": [
+                    "bootstrap.php"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Symfony Community",
+                    "homepage": "https://symfony.com/contributors"
+                },
+                {
+                    "name": "Gert de Pagter",
+                    "email": "backendtea@gmail.com"
+                }
+            ],
+            "description": "Symfony polyfill for ctype functions",
+            "homepage": "https://symfony.com",
+            "keywords": [
+                "compatibility",
+                "ctype",
+                "polyfill",
+                "portable"
+            ],
+            "time": "2019-02-06T07:57:58+00:00"
+        },
         {
             "name": "symfony/polyfill-intl-icu",
             "version": "v1.10.0",
@@ -6593,6 +6527,72 @@
             ],
             "time": "2018-12-05T18:34:18+00:00"
         },
+        {
+            "name": "twig/twig",
+            "version": "v1.38.4",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/twigphp/Twig.git",
+                "reference": "7732e9e7017d751313811bd118de61302e9c8b35"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/twigphp/Twig/zipball/7732e9e7017d751313811bd118de61302e9c8b35",
+                "reference": "7732e9e7017d751313811bd118de61302e9c8b35",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.4.0",
+                "symfony/polyfill-ctype": "^1.8"
+            },
+            "require-dev": {
+                "psr/container": "^1.0",
+                "symfony/debug": "^2.7",
+                "symfony/phpunit-bridge": "^3.4.19|^4.1.8"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.38-dev"
+                }
+            },
+            "autoload": {
+                "psr-0": {
+                    "Twig_": "lib/"
+                },
+                "psr-4": {
+                    "Twig\\": "src/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "BSD-3-Clause"
+            ],
+            "authors": [
+                {
+                    "name": "Fabien Potencier",
+                    "email": "fabien@symfony.com",
+                    "homepage": "http://fabien.potencier.org",
+                    "role": "Lead Developer"
+                },
+                {
+                    "name": "Armin Ronacher",
+                    "email": "armin.ronacher@active-4.com",
+                    "role": "Project Founder"
+                },
+                {
+                    "name": "Twig Team",
+                    "homepage": "https://twig.symfony.com/contributors",
+                    "role": "Contributors"
+                }
+            ],
+            "description": "Twig, the flexible, fast, and secure template language for PHP",
+            "homepage": "https://twig.symfony.com",
+            "keywords": [
+                "templating"
+            ],
+            "time": "2019-03-23T14:27:19+00:00"
+        },
         {
             "name": "umpirsky/twig-gettext-extractor",
             "version": "1.1.5",
diff --git a/lib/Config/Renderer.php b/lib/Config/Renderer.php
index 0fddce6f92..f26b87bfb7 100644
--- a/lib/Config/Renderer.php
+++ b/lib/Config/Renderer.php
@@ -3,15 +3,14 @@
 namespace MailPoet\Config;
 
 use MailPoet\Twig;
-use Twig_Environment as TwigEnv;
-use Twig_Lexer as TwigLexer;
-use Twig_Loader_Filesystem as TwigFileSystem;
+use MailPoetVendor\Twig_Environment as TwigEnv;
+use MailPoetVendor\Twig_Lexer as TwigLexer;
+use MailPoetVendor\Twig_Loader_Filesystem as TwigFileSystem;
 
 use MailPoet\WP\Functions as WPFunctions;
 
 if (!defined('ABSPATH')) exit;
 
-
 class Renderer {
   protected $cache_path;
   protected $caching_enabled;
@@ -103,7 +102,7 @@ class Renderer {
 
   function setupDebug() {
     if ($this->debugging_enabled) {
-      $this->renderer->addExtension(new \Twig_Extension_Debug());
+      $this->renderer->addExtension(new \MailPoetVendor\Twig_Extension_Debug());
     }
   }
 
diff --git a/lib/Config/RequirementsChecker.php b/lib/Config/RequirementsChecker.php
index 2b8f5d015c..80908c58d6 100644
--- a/lib/Config/RequirementsChecker.php
+++ b/lib/Config/RequirementsChecker.php
@@ -15,17 +15,11 @@ class RequirementsChecker {
   const TEST_MBSTRING_EXTENSION = 'MbstringExtension';
   const TEST_XML_EXTENSION = 'XmlExtension';
   const TEST_VENDOR_SOURCE = 'VendorSource';
-  const TWIG_SUPPORTED_VERSIONS = '1.26.0-1.34.4';
 
   public $display_error_notice;
   public $vendor_classes = array(
     '\ORM',
     '\Model',
-    '\Twig_Environment',
-    '\Twig_Loader_Filesystem',
-    '\Twig_Lexer',
-    '\Twig_Extension',
-    '\Twig_SimpleFunction',
     '\Swift_Mailer',
     '\Swift_SmtpTransport',
     '\Swift_Message',
@@ -131,30 +125,13 @@ class RequirementsChecker {
           $dependency_path
         );
 
-        $return_error = true;
-
-        // if a Twig dependency is loaded by another plugin, check for valid version
-        if (strpos($dependency, '\Twig_') === 0) {
-          $return_error = ($this->isValidTwigVersion()) ? false : $return_error;
-        }
-
-        if ($return_error) return $this->processError($error);
+        return $this->processError($error);
       }
     }
 
     return true;
   }
 
-  function isValidTwigVersion() {
-    list($minimum_version, $maximum_version) = explode('-', self::TWIG_SUPPORTED_VERSIONS);
-    return (
-      class_exists('\Twig_Environment') &&
-      defined('\Twig_Environment::VERSION') &&
-      version_compare(\Twig_Environment::VERSION, $minimum_version, '>=') &&
-      version_compare(\Twig_Environment::VERSION, $maximum_version, '<=')
-    );
-  }
-
   private function getDependencyPath($namespaced_class) {
     try {
       $reflector = new \ReflectionClass($namespaced_class);
diff --git a/lib/Twig/Analytics.php b/lib/Twig/Analytics.php
index a27cacf580..7f66ed9524 100644
--- a/lib/Twig/Analytics.php
+++ b/lib/Twig/Analytics.php
@@ -9,27 +9,27 @@ use MailPoet\WooCommerce\Helper as WooCommerceHelper;
 
 if (!defined('ABSPATH')) exit;
 
-class Analytics extends \Twig_Extension {
+class Analytics extends \MailPoetVendor\Twig_Extension {
   public function getFunctions() {
     $settings = new SettingsController();
     $analytics = new AnalyticsGenerator(new Reporter($settings, new WooCommerceHelper), $settings);
     return array(
-      new \Twig_SimpleFunction(
+      new \MailPoetVendor\Twig_SimpleFunction(
         'get_analytics_data',
         array($analytics, 'generateAnalytics'),
         array('is_safe' => array('all'))
       ),
-      new \Twig_SimpleFunction(
+      new \MailPoetVendor\Twig_SimpleFunction(
         'is_analytics_enabled',
         array($analytics, 'isEnabled'),
         array('is_safe' => array('all'))
       ),
-      new \Twig_SimpleFunction(
+      new \MailPoetVendor\Twig_SimpleFunction(
         'get_analytics_public_id',
         array($analytics, 'getPublicId'),
         array('is_safe' => array('all'))
       ),
-      new \Twig_SimpleFunction(
+      new \MailPoetVendor\Twig_SimpleFunction(
         'is_analytics_public_id_new',
         array($analytics, 'isPublicIdNew'),
         array('is_safe' => array('all'))
diff --git a/lib/Twig/Assets.php b/lib/Twig/Assets.php
index ddc4036fbb..249d47181a 100644
--- a/lib/Twig/Assets.php
+++ b/lib/Twig/Assets.php
@@ -5,7 +5,7 @@ use MailPoet\WP\Functions as WPFunctions;
 
 if (!defined('ABSPATH')) exit;
 
-class Assets extends \Twig_Extension {
+class Assets extends \MailPoetVendor\Twig_Extension {
   const CDN_URL = 'https://ps.w.org/mailpoet/';
   private $_globals;
 
@@ -15,22 +15,22 @@ class Assets extends \Twig_Extension {
 
   function getFunctions() {
     return array(
-      new \Twig_SimpleFunction(
+      new \MailPoetVendor\Twig_SimpleFunction(
         'stylesheet',
         array($this, 'generateStylesheet'),
         array('is_safe' => array('all'))
       ),
-      new \Twig_SimpleFunction(
+      new \MailPoetVendor\Twig_SimpleFunction(
         'javascript',
         array($this, 'generateJavascript'),
         array('is_safe' => array('all'))
       ),
-      new \Twig_SimpleFunction(
+      new \MailPoetVendor\Twig_SimpleFunction(
         'image_url',
         array($this, 'generateImageUrl'),
         array('is_safe' => array('all'))
       ),
-      new \Twig_SimpleFunction(
+      new \MailPoetVendor\Twig_SimpleFunction(
         'cdn_url',
         array($this, 'generateCdnUrl'),
         array('is_safe' => array('all'))
diff --git a/lib/Twig/Filters.php b/lib/Twig/Filters.php
index f40f6986fb..1d39166817 100644
--- a/lib/Twig/Filters.php
+++ b/lib/Twig/Filters.php
@@ -4,7 +4,7 @@ namespace MailPoet\Twig;
 
 if (!defined('ABSPATH')) exit;
 
-class Filters extends \Twig_Extension {
+class Filters extends \MailPoetVendor\Twig_Extension {
 
   function getName() {
     return 'filters';
@@ -12,11 +12,11 @@ class Filters extends \Twig_Extension {
 
   function getFilters() {
     return array(
-      new \Twig_SimpleFilter(
+      new \MailPoetVendor\Twig_SimpleFilter(
         'intval',
         'intval'
       ),
-      new \Twig_SimpleFilter(
+      new \MailPoetVendor\Twig_SimpleFilter(
         'replaceLinkTags',
         'MailPoet\Util\Helpers::replaceLinkTags'
       )
diff --git a/lib/Twig/Functions.php b/lib/Twig/Functions.php
index d3c82604f3..bafb5703ab 100644
--- a/lib/Twig/Functions.php
+++ b/lib/Twig/Functions.php
@@ -10,7 +10,7 @@ use MailPoet\WP\Functions as WPFunctions;
 
 if (!defined('ABSPATH')) exit;
 
-class Functions extends \Twig_Extension {
+class Functions extends \MailPoetVendor\Twig_Extension {
 
   /** @var SettingsController */
   private $settings;
@@ -21,97 +21,97 @@ class Functions extends \Twig_Extension {
 
   function getFunctions() {
     return array(
-      new \Twig_SimpleFunction(
+      new \MailPoetVendor\Twig_SimpleFunction(
         'json_encode',
         'json_encode',
         array('is_safe' => array('all'))
       ),
-      new \Twig_SimpleFunction(
+      new \MailPoetVendor\Twig_SimpleFunction(
         'json_decode',
         'json_decode',
         array('is_safe' => array('all'))
       ),
-      new \Twig_SimpleFunction(
+      new \MailPoetVendor\Twig_SimpleFunction(
         'wp_nonce_field',
         'wp_nonce_field',
         array('is_safe' => array('all'))
       ),
-      new \Twig_SimpleFunction(
+      new \MailPoetVendor\Twig_SimpleFunction(
         'params',
         array($this, 'params'),
         array('is_safe' => array('all'))
       ),
-      new \Twig_SimpleFunction(
+      new \MailPoetVendor\Twig_SimpleFunction(
         'admin_url',
         'admin_url',
         array('is_safe' => array('all'))
       ),
-      new \Twig_SimpleFunction(
+      new \MailPoetVendor\Twig_SimpleFunction(
         'get_option',
         'get_option',
         array('is_safe' => array('all'))
       ),
-      new \Twig_SimpleFunction(
+      new \MailPoetVendor\Twig_SimpleFunction(
         'get_option',
         'get_option',
         array('is_safe' => array('all'))
       ),
-      new \Twig_SimpleFunction(
+      new \MailPoetVendor\Twig_SimpleFunction(
         'sending_frequency',
         array($this, 'getSendingFrequency'),
         array('is_safe' => array('all'))
       ),
-      new \Twig_SimpleFunction(
+      new \MailPoetVendor\Twig_SimpleFunction(
         'wp_date_format',
         array($this, 'getWPDateFormat'),
         array('is_safe' => array('all'))
       ),
-      new \Twig_SimpleFunction(
+      new \MailPoetVendor\Twig_SimpleFunction(
         'mailpoet_version',
         array($this, 'getMailPoetVersion'),
         array('is_safe' => array('all'))
       ),
-      new \Twig_SimpleFunction(
+      new \MailPoetVendor\Twig_SimpleFunction(
         'mailpoet_premium_version',
         array($this, 'getMailPoetPremiumVersion'),
         array('is_safe' => array('all'))
       ),
-      new \Twig_SimpleFunction(
+      new \MailPoetVendor\Twig_SimpleFunction(
         'mailpoet_has_valid_premium_key',
         array($this, 'hasValidPremiumKey'),
         array('is_safe' => array('all'))
       ),
-      new \Twig_SimpleFunction(
+      new \MailPoetVendor\Twig_SimpleFunction(
         'wp_time_format',
         array($this, 'getWPTimeFormat'),
         array('is_safe' => array('all'))
       ),
-      new \Twig_SimpleFunction(
+      new \MailPoetVendor\Twig_SimpleFunction(
         'wp_datetime_format',
         array($this, 'getWPDateTimeFormat'),
         array('is_safe' => array('all'))
       ),
-      new \Twig_SimpleFunction(
+      new \MailPoetVendor\Twig_SimpleFunction(
         'do_action',
         'do_action',
         array('is_safe' => array('all'))
       ),
-      new \Twig_SimpleFunction(
+      new \MailPoetVendor\Twig_SimpleFunction(
         'is_rtl',
         array($this, 'isRtl'),
         array('is_safe' => array('all'))
       ),
-      new \Twig_SimpleFunction(
+      new \MailPoetVendor\Twig_SimpleFunction(
         'number_format_i18n',
         'number_format_i18n',
         array('is_safe' => array('all'))
       ),
-      new \Twig_SimpleFunction(
+      new \MailPoetVendor\Twig_SimpleFunction(
         'mailpoet_locale',
         array($this, 'getTwoLettersLocale'),
         array('is_safe' => array('all'))
       ),
-      new \Twig_SimpleFunction(
+      new \MailPoetVendor\Twig_SimpleFunction(
         'mailpoet_free_domains',
         array($this, 'getFreeDomains'),
         array('is_safe' => array('all'))
diff --git a/lib/Twig/Handlebars.php b/lib/Twig/Handlebars.php
index 4030b876fc..cea69955be 100644
--- a/lib/Twig/Handlebars.php
+++ b/lib/Twig/Handlebars.php
@@ -4,10 +4,10 @@ namespace MailPoet\Twig;
 
 if (!defined('ABSPATH')) exit;
 
-class Handlebars extends \Twig_Extension {
+class Handlebars extends \MailPoetVendor\Twig_Extension {
   public function getFunctions() {
     return array(
-      new \Twig_SimpleFunction(
+      new \MailPoetVendor\Twig_SimpleFunction(
         'partial',
         array(
           $this,
@@ -41,7 +41,7 @@ class Handlebars extends \Twig_Extension {
         return;
     }
 
-    $rendered_template = twig_include($env, $context, $file);
+    $rendered_template = \MailPoetVendor\twig_include($env, $context, $file);
 
     $output = <<<EOL
 <script id="$id" type="text/x-handlebars-template">
diff --git a/lib/Twig/Helpscout.php b/lib/Twig/Helpscout.php
index f9af1d1e64..2a0f5ee7a0 100644
--- a/lib/Twig/Helpscout.php
+++ b/lib/Twig/Helpscout.php
@@ -4,10 +4,10 @@ namespace MailPoet\Twig;
 
 if (!defined('ABSPATH')) exit;
 
-class Helpscout extends \Twig_Extension {
+class Helpscout extends \MailPoetVendor\Twig_Extension {
   public function getFunctions() {
     return array(
-      new \Twig_SimpleFunction(
+      new \MailPoetVendor\Twig_SimpleFunction(
         'get_helpscout_data',
         '\MailPoet\Helpscout\Beacon::getData',
         array('is_safe' => array('all'))
diff --git a/lib/Twig/I18n.php b/lib/Twig/I18n.php
index 9689196862..731dca5c28 100644
--- a/lib/Twig/I18n.php
+++ b/lib/Twig/I18n.php
@@ -7,7 +7,7 @@ use MailPoet\WP\Functions as WPFunctions;
 
 if (!defined('ABSPATH')) exit;
 
-class I18n extends \Twig_Extension {
+class I18n extends \MailPoetVendor\Twig_Extension {
 
   private $_text_domain;
 
@@ -30,7 +30,7 @@ class I18n extends \Twig_Extension {
     );
 
     foreach ($functions as $twig_function => $function) {
-      $twig_functions[] = new \Twig_SimpleFunction(
+      $twig_functions[] = new \MailPoetVendor\Twig_SimpleFunction(
         $twig_function,
         array($this, $function),
         array('is_safe' => array('all'))
diff --git a/lib/Twig/Polls.php b/lib/Twig/Polls.php
index 9b89ec949d..a564399cb4 100644
--- a/lib/Twig/Polls.php
+++ b/lib/Twig/Polls.php
@@ -6,7 +6,7 @@ use MailPoet\Settings\SettingsController;
 
 if (!defined('ABSPATH')) exit;
 
-class Polls extends \Twig_Extension {
+class Polls extends \MailPoetVendor\Twig_Extension {
 
   /** @var SettingsController */
   private $settings;
@@ -17,12 +17,12 @@ class Polls extends \Twig_Extension {
 
   public function getFunctions() {
     return array(
-      new \Twig_SimpleFunction(
+      new \MailPoetVendor\Twig_SimpleFunction(
         'get_polls_data',
         array($this, 'getPollsData'),
         array('is_safe' => array('all'))
       ),
-      new \Twig_SimpleFunction(
+      new \MailPoetVendor\Twig_SimpleFunction(
         'get_polls_visiblity',
         array($this, 'getPollsVisibility'),
         array('is_safe' => array('all'))
diff --git a/prefixer/composer.json b/prefixer/composer.json
index 36094d2e55..0ab6560ede 100644
--- a/prefixer/composer.json
+++ b/prefixer/composer.json
@@ -3,7 +3,8 @@
     "php": ">=5.6",
     "symfony/dependency-injection": "3.4.22",
     "monolog/monolog": "^1.23",
-    "sabberworm/php-css-parser": "^8.1"
+    "sabberworm/php-css-parser": "^8.1",
+    "twig/twig": "1.38.4"
   },
   "scripts": {
     "post-update-cmd": "@process",
@@ -12,7 +13,8 @@
       "rm -rf ../vendor-prefixed",
       "mkdir ../vendor-prefixed",
       "../php-scoper.phar add-prefix",
-      "mv ./build/* ../vendor-prefixed"
+      "mv ./build/* ../vendor-prefixed",
+      "php fix-twig.php"
     ]
   },
   "config": {
diff --git a/prefixer/composer.lock b/prefixer/composer.lock
index 443383039a..70f97775a4 100644
--- a/prefixer/composer.lock
+++ b/prefixer/composer.lock
@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "5adf957548a314d23d716c2e5959e24b",
+    "content-hash": "0a85a5163c915ee5e4c5e546973aa767",
     "packages": [
         {
             "name": "monolog/monolog",
@@ -294,6 +294,130 @@
             "description": "Symfony DependencyInjection Component",
             "homepage": "https://symfony.com",
             "time": "2019-01-30T17:48:51+00:00"
+        },
+        {
+            "name": "symfony/polyfill-ctype",
+            "version": "v1.11.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/symfony/polyfill-ctype.git",
+                "reference": "82ebae02209c21113908c229e9883c419720738a"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/symfony/polyfill-ctype/zipball/82ebae02209c21113908c229e9883c419720738a",
+                "reference": "82ebae02209c21113908c229e9883c419720738a",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.3.3"
+            },
+            "suggest": {
+                "ext-ctype": "For best performance"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.11-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Symfony\\Polyfill\\Ctype\\": ""
+                },
+                "files": [
+                    "bootstrap.php"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Symfony Community",
+                    "homepage": "https://symfony.com/contributors"
+                },
+                {
+                    "name": "Gert de Pagter",
+                    "email": "backendtea@gmail.com"
+                }
+            ],
+            "description": "Symfony polyfill for ctype functions",
+            "homepage": "https://symfony.com",
+            "keywords": [
+                "compatibility",
+                "ctype",
+                "polyfill",
+                "portable"
+            ],
+            "time": "2019-02-06T07:57:58+00:00"
+        },
+        {
+            "name": "twig/twig",
+            "version": "v1.38.4",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/twigphp/Twig.git",
+                "reference": "7732e9e7017d751313811bd118de61302e9c8b35"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/twigphp/Twig/zipball/7732e9e7017d751313811bd118de61302e9c8b35",
+                "reference": "7732e9e7017d751313811bd118de61302e9c8b35",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.4.0",
+                "symfony/polyfill-ctype": "^1.8"
+            },
+            "require-dev": {
+                "psr/container": "^1.0",
+                "symfony/debug": "^2.7",
+                "symfony/phpunit-bridge": "^3.4.19|^4.1.8"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.38-dev"
+                }
+            },
+            "autoload": {
+                "psr-0": {
+                    "Twig_": "lib/"
+                },
+                "psr-4": {
+                    "Twig\\": "src/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "BSD-3-Clause"
+            ],
+            "authors": [
+                {
+                    "name": "Fabien Potencier",
+                    "email": "fabien@symfony.com",
+                    "homepage": "http://fabien.potencier.org",
+                    "role": "Lead Developer"
+                },
+                {
+                    "name": "Armin Ronacher",
+                    "email": "armin.ronacher@active-4.com",
+                    "role": "Project Founder"
+                },
+                {
+                    "name": "Twig Team",
+                    "homepage": "https://twig.symfony.com/contributors",
+                    "role": "Contributors"
+                }
+            ],
+            "description": "Twig, the flexible, fast, and secure template language for PHP",
+            "homepage": "https://twig.symfony.com",
+            "keywords": [
+                "templating"
+            ],
+            "time": "2019-03-23T14:27:19+00:00"
         }
     ],
     "packages-dev": [],
diff --git a/prefixer/fix-twig.php b/prefixer/fix-twig.php
new file mode 100755
index 0000000000..8aea2ba295
--- /dev/null
+++ b/prefixer/fix-twig.php
@@ -0,0 +1,238 @@
+<?php
+
+$replacements = [
+  [
+    'file' => '../vendor-prefixed/twig/twig/src/ExpressionParser.php',
+    'find' => [
+      '\'Twig\\\\Node\\\\Expression\\\\TestExpression\'',
+      '\'Twig\\\\Node\\\\Expression\\\\FunctionExpression\'',
+      '\'Twig\\\\Node\\\\Expression\\\\FilterExpression\'',
+    ],
+    'replace' => [
+      '\'MailPoetVendor\\\\Twig\\\\Node\\\\Expression\\\\TestExpression\'',
+      '\'MailPoetVendor\\\\Twig\\\\Node\\\\Expression\\\\FunctionExpression\'',
+      '\'MailPoetVendor\\\\Twig\\\\Node\\\\Expression\\\\FilterExpression\'',
+    ],
+  ],
+  [
+    'file' => '../vendor-prefixed/twig/twig/src/TwigFilter.php',
+    'find' => [
+      '\'\\\\Twig\\\\Node\\\\Expression\\\\FilterExpression\'',
+    ],
+    'replace' => [
+      '\'\\\\MailPoetVendor\\\\Twig\\\\Node\\\\Expression\\\\FilterExpression\'',
+    ],
+  ],
+  [
+    'file' => '../vendor-prefixed/twig/twig/src/TwigFunction.php',
+    'find' => [
+      '\'\\\\Twig\\\\Node\\\\Expression\\\\FunctionExpression\'',
+    ],
+    'replace' => [
+      '\'\\\\MailPoetVendor\\\\Twig\\\\Node\\\\Expression\\\\FunctionExpression\'',
+    ],
+  ],
+  [
+    'file' => '../vendor-prefixed/twig/twig/src/TwigTest.php',
+    'find' => [
+      '\'\\\\Twig\\\\Node\\\\Expression\\\\TestExpression\'',
+    ],
+    'replace' => [
+      '\'\\\\MailPoetVendor\\\\Twig\\\\Node\\\\Expression\\\\TestExpression\'',
+    ],
+  ],
+  [
+    'file' => '../vendor-prefixed/twig/twig/src/Node/Expression/Binary/NotInBinary.php',
+    'find' => [
+      '\'!twig_in_filter(\''
+    ],
+    'replace' => [
+      '\'!\\\\MailPoetVendor\\\\twig_in_filter(\'',
+    ],
+  ],
+  [
+    'file' => '../vendor-prefixed/twig/twig/src/Node/Expression/Binary/InBinary.php',
+    'find' => [
+      '\'twig_in_filter(\''
+    ],
+    'replace' => [
+      '\'\\\\MailPoetVendor\\\\twig_in_filter(\'',
+    ],
+  ],
+  [
+    'file' => '../vendor-prefixed/twig/twig/src/Extension/CoreExtension.php',
+    'find' => [
+      '\'twig_date_format_filter\'',
+      '\'twig_date_modify_filter\'',
+      '\'twig_replace_filter\'',
+      '\'twig_number_format_filter\'',
+      '\'twig_round\'',
+      '\'twig_urlencode_filter\'',
+      '\'twig_jsonencode_filter\'',
+      '\'twig_convert_encoding\'',
+      '\'twig_title_string_filter\'',
+      '\'twig_capitalize_string_filter\'',
+      '\'twig_trim_filter\'',
+      '\'twig_spaceless\'',
+      '\'twig_join_filter\'',
+      '\'twig_split_filter\'',
+      '\'twig_sort_filter\'',
+      '\'twig_sort_filter\'',
+      '\'twig_array_batch\'',
+      '\'twig_reverse_filter\'',
+      '\'twig_length_filter\'',
+      '\'twig_slice\'',
+      '\'twig_first\'',
+      '\'twig_last\'',
+      '\'_twig_default_filter\'',
+      '\'twig_get_array_keys_filter\'',
+      '\'twig_escape_filter\'',
+      '\'twig_upper_filter\'',
+      '\'twig_lower_filter\'',
+      '\'twig_escape_filter_is_safe\'',
+      '\'_twig_escape_js_callback\'',
+      '\'_twig_escape_css_callback\'',
+      '\'_twig_escape_html_attr_callback\'',
+      '\'twig_source\'',
+      '\'twig_test_empty\'',
+      '\'_twig_markup2string\'',
+      '\'twig_test_iterable\'',
+      '\'twig_random\'',
+      '\'twig_date_converter\'',
+      '\'twig_cycle\'',
+      '\'twig_constant\'',
+    ],
+    'replace' => [
+      '\'\\\\MailPoetVendor\\\\twig_date_format_filter\'',
+      '\'\\\\MailPoetVendor\\\\twig_date_modify_filter\'',
+      '\'\\\\MailPoetVendor\\\\twig_replace_filter\'',
+      '\'\\\\MailPoetVendor\\\\twig_number_format_filter\'',
+      '\'\\\\MailPoetVendor\\\\twig_round\'',
+      '\'\\\\MailPoetVendor\\\\twig_urlencode_filter\'',
+      '\'\\\\MailPoetVendor\\\\twig_jsonencode_filter\'',
+      '\'\\\\MailPoetVendor\\\\twig_convert_encoding\'',
+      '\'\\\\MailPoetVendor\\\\twig_title_string_filter\'',
+      '\'\\\\MailPoetVendor\\\\twig_capitalize_string_filter\'',
+      '\'\\\\MailPoetVendor\\\\twig_trim_filter\'',
+      '\'\\\\MailPoetVendor\\\\twig_spaceless\'',
+      '\'\\\\MailPoetVendor\\\\twig_join_filter\'',
+      '\'\\\\MailPoetVendor\\\\twig_split_filter\'',
+      '\'\\\\MailPoetVendor\\\\twig_sort_filter\'',
+      '\'\\\\MailPoetVendor\\\\twig_array_merge\'',
+      '\'\\\\MailPoetVendor\\\\twig_array_batch\'',
+      '\'\\\\MailPoetVendor\\\\twig_reverse_filter\'',
+      '\'\\\\MailPoetVendor\\\\twig_length_filter\'',
+      '\'\\\\MailPoetVendor\\\\twig_slice\'',
+      '\'\\\\MailPoetVendor\\\\twig_first\'',
+      '\'\\\\MailPoetVendor\\\\twig_last\'',
+      '\'\\\\MailPoetVendor\\\\_twig_default_filter\'',
+      '\'\\\\MailPoetVendor\\\\twig_get_array_keys_filter\'',
+      '\'\\\\MailPoetVendor\\\\twig_escape_filter\'',
+      '\'\\\\MailPoetVendor\\\\twig_upper_filter\'',
+      '\'\\\\MailPoetVendor\\\\twig_lower_filter\'',
+      '\'\\\\MailPoetVendor\\\\twig_escape_filter_is_safe\'',
+      '\'\\\\MailPoetVendor\\\\_twig_escape_js_callback\'',
+      '\'\\\\MailPoetVendor\\\\_twig_escape_css_callback\'',
+      '\'\\\\MailPoetVendor\\\\_twig_escape_html_attr_callback\'',
+      '\'\\\\MailPoetVendor\\\\twig_source\'',
+      '\'\\\\MailPoetVendor\\\\twig_test_empty\'',
+      '\'\\\\MailPoetVendor\\\\_twig_markup2string\'',
+      '\'\\\\MailPoetVendor\\\\twig_test_iterable\'',
+      '\'\\\\MailPoetVendor\\\\twig_random\'',
+      '\'\\\\MailPoetVendor\\\\twig_date_converter\'',
+      '\'\\\\MailPoetVendor\\\\twig_cycle\'',
+      '\'\\\\MailPoetVendor\\\\twig_constant\'',
+    ],
+  ],
+  [
+    'file' => '../vendor-prefixed/twig/twig/src/Node/ForNode.php',
+    'find' => [
+      '= twig_ensure_traversable("',
+    ],
+    'replace' => [
+      '= \\\\MailPoetVendor\\\\twig_ensure_traversable("',
+    ],
+  ],
+  [
+    'file' => '../vendor-prefixed/twig/twig/src/Node/CheckSecurityNode.php',
+    'find' => [
+      '\'\\\\Twig\\\\Extension\\\\SandboxExtension\'',
+    ],
+    'replace' => [
+      '\'\\\\MailPoetVendor\\\\Twig\\\\Extension\\\\SandboxExtension\'',
+    ],
+  ],
+  [
+    'file' => '../vendor-prefixed/twig/twig/src/Node/SandboxedPrintNode.php',
+    'find' => [
+      '\'\\\\Twig\\\\Extension\\\\SandboxExtension',
+    ],
+    'replace' => [
+      '\'\\\\MailPoetVendor\\\\Twig\\\\Extension\\\\SandboxExtension',
+    ],
+  ],
+  [
+    'file' => '../vendor-prefixed/twig/twig/src/Environment.php',
+    'find' => [
+      '\'\\\\Twig\\\\Template\'',
+      '\'Twig_Extension\'',
+      '\'Twig\\\\Extension\\\\AbstractExtension\'',
+    ],
+    'replace' => [
+      '\'\\\\MailPoetVendor\\\\Twig\\\\Template\'',
+      '\'MailPoetVendor\\\\Twig_Extension\'',
+      '\'MailPoetVendor\\\\Twig\\\\Extension\\\\AbstractExtension\'',
+    ],
+  ],
+  [
+    'file' => '../vendor-prefixed/twig/twig/src/Token.php',
+    'find' => [
+      '\'Twig\\\\Token::\'',
+    ],
+    'replace' => [
+      '\'MailPoetVendor\\\\Twig\\\\Token::\'',
+    ],
+  ],
+  [
+    'file' => '../vendor-prefixed/twig/twig/src/Profiler/Node/EnterProfileNode.php',
+    'find' => [
+      '\\\\Twig\\\\Profiler\\\\Profile',
+    ],
+    'replace' => [
+      '\\\\MailPoetVendor\\\\Twig\\\\Profiler\\\\Profile',
+    ],
+  ],
+  [
+    'file' => '../vendor-prefixed/twig/twig/src/Node/ModuleNode.php',
+    'find' => [
+      '"use Twig\\\\Environment;',
+      '"use Twig\\\\Markup;',
+      '"use Twig\\\\Source;',
+      '"use Twig\\\\Template;',
+      '"use Twig\\\\Error\\\\LoaderError;',
+      '"use Twig\\\\Error\\\\RuntimeError;',
+      '"use Twig\\\\Sandbox\\\\SecurityError;',
+      '"use Twig\\\\Sandbox\\\\SecurityNotAllowedTagError;',
+      '"use Twig\\\\Sandbox\\\\SecurityNotAllowedFilterError;',
+      '"use Twig\\\\Sandbox\\\\SecurityNotAllowedFunctionError;',
+    ],
+    'replace' => [
+      '"use MailPoetVendor\\\\Twig\\\\Environment;',
+      '"use MailPoetVendor\\\\Twig\\\\Markup;',
+      '"use MailPoetVendor\\\\Twig\\\\Source;',
+      '"use MailPoetVendor\\\\Twig\\\\Template;',
+      '"use MailPoetVendor\\\\Twig\\\\Error\\\\LoaderError;',
+      '"use MailPoetVendor\\\\Twig\\\\Error\\\\RuntimeError;',
+      '"use MailPoetVendor\\\\Twig\\\\Sandbox\\\\SecurityError;',
+      '"use MailPoetVendor\\\\Twig\\\\Sandbox\\\\SecurityNotAllowedTagError;',
+      '"use MailPoetVendor\\\\Twig\\\\Sandbox\\\\SecurityNotAllowedFilterError;',
+      '"use MailPoetVendor\\\\Twig\\\\Sandbox\\\\SecurityNotAllowedFunctionError;',
+    ],
+  ],
+];
+
+foreach ($replacements as $single_file) {
+  $data = file_get_contents($single_file['file']);
+  $data = str_replace($single_file['find'], $single_file['replace'], $data);
+  file_put_contents($single_file['file'], $data);
+}
diff --git a/tests/integration/Config/RendererTest.php b/tests/integration/Config/RendererTest.php
index 71b596f741..3948666de1 100644
--- a/tests/integration/Config/RendererTest.php
+++ b/tests/integration/Config/RendererTest.php
@@ -5,6 +5,7 @@ use Codeception\Stub;
 use Codeception\Stub\Expected;
 use MailPoet\Config\Env;
 use MailPoet\Config\Renderer;
+use MailPoetVendor\Twig_Environment;
 
 class RendererTest extends \MailPoetTest {
   function _before() {
@@ -75,7 +76,7 @@ class RendererTest extends \MailPoetTest {
       $this->renderer,
       array(),
       array(
-        'renderer' => Stub::makeEmpty('Twig_Environment',
+        'renderer' => Stub::makeEmpty(Twig_Environment::class,
           array(
             'render' => Expected::atLeastOnce(function() {
               return 'test render';
@@ -95,7 +96,7 @@ class RendererTest extends \MailPoetTest {
       $this->renderer,
       array(true, false),
       array(
-        'renderer' => Stub::makeEmpty('Twig_Environment',
+        'renderer' => Stub::makeEmpty(Twig_Environment::class,
           array(
             'render' => Expected::atLeastOnce(function() use ($exception_message) {
               throw new \RuntimeException($exception_message);
diff --git a/tests/integration/Twig/FunctionsTest.php b/tests/integration/Twig/FunctionsTest.php
index 30913afa29..16b00beb98 100644
--- a/tests/integration/Twig/FunctionsTest.php
+++ b/tests/integration/Twig/FunctionsTest.php
@@ -9,7 +9,7 @@ use MailPoet\WP\Functions as WPFunctions;
 class FunctionsTest extends \MailPoetTest {
   function testItExecutesIsRtlFunction() {
     $template = array('template' => '{% if is_rtl() %}rtl{% endif %}');
-    $twig = new \Twig_Environment(new \Twig_Loader_Array($template));
+    $twig = new \MailPoetVendor\Twig_Environment(new \MailPoetVendor\Twig_Loader_Array($template));
     $twig->addExtension(new Functions());
 
     WPFunctions::set(Stub::make(new WPFunctions, [