diff --git a/composer.json b/composer.json
index 94f5b545d2..e04604d85d 100644
--- a/composer.json
+++ b/composer.json
@@ -37,8 +37,8 @@
     "vlucas/phpdotenv": "^2.4.0",
     "umpirsky/twig-gettext-extractor": "1.1.*",
     "kint-php/kint": "^2.2",
-    "squizlabs/php_codesniffer": "^2.8.1",
-    "wimg/php-compatibility": "^7.1.2",
+    "squizlabs/php_codesniffer": "^3.3",
+    "phpcompatibility/php-compatibility": "^9.0",
     "coenjacobs/mozart": "^0.2.2"
   },
   "autoload": {
@@ -48,8 +48,8 @@
     }
   },
   "scripts": {
-    "post-update-cmd": "\"vendor/bin/mozart\" compose; rm -rf vendor/monolog; rm -rf vendor/squizlabs/php_codesniffer/CodeSniffer/Standards/PHPCompatibility; cp -rp vendor/wimg/php-compatibility vendor/squizlabs/php_codesniffer/CodeSniffer/Standards/PHPCompatibility",
-    "post-install-cmd": "\"vendor/bin/mozart\" compose; rm -rf vendor/monolog; rm -rf vendor/squizlabs/php_codesniffer/CodeSniffer/Standards/PHPCompatibility; cp -rp vendor/wimg/php-compatibility vendor/squizlabs/php_codesniffer/CodeSniffer/Standards/PHPCompatibility"
+    "post-update-cmd": "\"vendor/bin/mozart\" compose; rm -rf vendor/monolog",
+    "post-install-cmd": "\"vendor/bin/mozart\" compose; rm -rf vendor/monolog"
   },
   "extra": {
     "mozart": {
diff --git a/composer.lock b/composer.lock
index a6c6748707..9957898903 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": "1b1dc65d1395527fdd6c951aa43f8cb9",
+    "content-hash": "cb44256ac266ac704c6dd361cb3ea816",
     "packages": [
         {
             "name": "cerdic/css-tidy",
@@ -4066,6 +4066,64 @@
             ],
             "time": "2018-07-04T16:31:37+00:00"
         },
+        {
+            "name": "phpcompatibility/php-compatibility",
+            "version": "9.0.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/PHPCompatibility/PHPCompatibility.git",
+                "reference": "e9f4047e5edf53c88f36f1dafc0d49454ce13e25"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/PHPCompatibility/PHPCompatibility/zipball/e9f4047e5edf53c88f36f1dafc0d49454ce13e25",
+                "reference": "e9f4047e5edf53c88f36f1dafc0d49454ce13e25",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=5.3",
+                "squizlabs/php_codesniffer": "^2.3 || ^3.0.2"
+            },
+            "conflict": {
+                "squizlabs/php_codesniffer": "2.6.2"
+            },
+            "require-dev": {
+                "phpunit/phpunit": "~4.5 || ^5.0 || ^6.0 || ^7.0"
+            },
+            "suggest": {
+                "dealerdirect/phpcodesniffer-composer-installer": "^0.4.3 || This Composer plugin will sort out the PHPCS 'installed_paths' automatically.",
+                "roave/security-advisories": "dev-master || Helps prevent installing dependencies with known security issues."
+            },
+            "type": "phpcodesniffer-standard",
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "LGPL-3.0-or-later"
+            ],
+            "authors": [
+                {
+                    "name": "Contributors",
+                    "homepage": "https://github.com/PHPCompatibility/PHPCompatibility/graphs/contributors"
+                },
+                {
+                    "name": "Wim Godden",
+                    "homepage": "https://github.com/wimg",
+                    "role": "lead"
+                },
+                {
+                    "name": "Juliette Reinders Folmer",
+                    "homepage": "https://github.com/jrfnl",
+                    "role": "lead"
+                }
+            ],
+            "description": "A set of sniffs for PHP_CodeSniffer that checks for PHP cross-version compatibility.",
+            "homepage": "http://techblog.wimgodden.be/tag/codesniffer/",
+            "keywords": [
+                "compatibility",
+                "phpcs",
+                "standards"
+            ],
+            "time": "2018-10-07T17:38:02+00:00"
+        },
         {
             "name": "phpdocumentor/reflection-common",
             "version": "1.0.1",
@@ -5466,64 +5524,37 @@
         },
         {
             "name": "squizlabs/php_codesniffer",
-            "version": "2.9.1",
+            "version": "3.3.2",
             "source": {
                 "type": "git",
                 "url": "https://github.com/squizlabs/PHP_CodeSniffer.git",
-                "reference": "dcbed1074f8244661eecddfc2a675430d8d33f62"
+                "reference": "6ad28354c04b364c3c71a34e4a18b629cc3b231e"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/squizlabs/PHP_CodeSniffer/zipball/dcbed1074f8244661eecddfc2a675430d8d33f62",
-                "reference": "dcbed1074f8244661eecddfc2a675430d8d33f62",
+                "url": "https://api.github.com/repos/squizlabs/PHP_CodeSniffer/zipball/6ad28354c04b364c3c71a34e4a18b629cc3b231e",
+                "reference": "6ad28354c04b364c3c71a34e4a18b629cc3b231e",
                 "shasum": ""
             },
             "require": {
                 "ext-simplexml": "*",
                 "ext-tokenizer": "*",
                 "ext-xmlwriter": "*",
-                "php": ">=5.1.2"
+                "php": ">=5.4.0"
             },
             "require-dev": {
-                "phpunit/phpunit": "~4.0"
+                "phpunit/phpunit": "^4.0 || ^5.0 || ^6.0 || ^7.0"
             },
             "bin": [
-                "scripts/phpcs",
-                "scripts/phpcbf"
+                "bin/phpcs",
+                "bin/phpcbf"
             ],
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-master": "2.x-dev"
+                    "dev-master": "3.x-dev"
                 }
             },
-            "autoload": {
-                "classmap": [
-                    "CodeSniffer.php",
-                    "CodeSniffer/CLI.php",
-                    "CodeSniffer/Exception.php",
-                    "CodeSniffer/File.php",
-                    "CodeSniffer/Fixer.php",
-                    "CodeSniffer/Report.php",
-                    "CodeSniffer/Reporting.php",
-                    "CodeSniffer/Sniff.php",
-                    "CodeSniffer/Tokens.php",
-                    "CodeSniffer/Reports/",
-                    "CodeSniffer/Tokenizers/",
-                    "CodeSniffer/DocGenerators/",
-                    "CodeSniffer/Standards/AbstractPatternSniff.php",
-                    "CodeSniffer/Standards/AbstractScopeSniff.php",
-                    "CodeSniffer/Standards/AbstractVariableSniff.php",
-                    "CodeSniffer/Standards/IncorrectPatternException.php",
-                    "CodeSniffer/Standards/Generic/Sniffs/",
-                    "CodeSniffer/Standards/MySource/Sniffs/",
-                    "CodeSniffer/Standards/PEAR/Sniffs/",
-                    "CodeSniffer/Standards/PSR1/Sniffs/",
-                    "CodeSniffer/Standards/PSR2/Sniffs/",
-                    "CodeSniffer/Standards/Squiz/Sniffs/",
-                    "CodeSniffer/Standards/Zend/Sniffs/"
-                ]
-            },
             "notification-url": "https://packagist.org/downloads/",
             "license": [
                 "BSD-3-Clause"
@@ -5540,7 +5571,7 @@
                 "phpcs",
                 "standards"
             ],
-            "time": "2017-05-22T02:43:20+00:00"
+            "time": "2018-09-23T23:08:17+00:00"
         },
         {
             "name": "symfony/browser-kit",
@@ -6792,50 +6823,6 @@
             ],
             "time": "2018-01-29T19:49:41+00:00"
         },
-        {
-            "name": "wimg/php-compatibility",
-            "version": "7.1.5",
-            "source": {
-                "type": "git",
-                "url": "https://github.com/wimg/PHPCompatibility.git",
-                "reference": "1649732fb1a2115608dfe805a644e4405fb6444b"
-            },
-            "dist": {
-                "type": "zip",
-                "url": "https://api.github.com/repos/wimg/PHPCompatibility/zipball/1649732fb1a2115608dfe805a644e4405fb6444b",
-                "reference": "1649732fb1a2115608dfe805a644e4405fb6444b",
-                "shasum": ""
-            },
-            "require": {
-                "ext-tokenizer": "*",
-                "php": ">=5.1.2",
-                "squizlabs/php_codesniffer": "^2.0"
-            },
-            "type": "phpcodesniffer-standard",
-            "autoload": {
-                "psr-4": {
-                    "PHPCompatibility\\": ""
-                }
-            },
-            "notification-url": "https://packagist.org/downloads/",
-            "license": [
-                "LGPL-3.0"
-            ],
-            "authors": [
-                {
-                    "name": "Wim Godden",
-                    "role": "lead"
-                }
-            ],
-            "description": "This is a set of sniffs for PHP_CodeSniffer that checks for PHP version compatibility.",
-            "homepage": "http://techblog.wimgodden.be/tag/codesniffer/",
-            "keywords": [
-                "compatibility",
-                "phpcs",
-                "standards"
-            ],
-            "time": "2017-07-15T23:03:53+00:00"
-        },
         {
             "name": "wp-cli/autoload-splitter",
             "version": "v0.1.5",
diff --git a/lib/Form/Widget.php b/lib/Form/Widget.php
index ab499159e6..8e3f5b47f6 100644
--- a/lib/Form/Widget.php
+++ b/lib/Form/Widget.php
@@ -209,7 +209,7 @@ EOL;
         <?php
         foreach($forms as $form) {
           $is_selected = ($selected_form === (int)$form['id']) ? 'selected="selected"' : '';
-        ?>
+          ?>
         <option value="<?php echo (int)$form['id']; ?>" <?php echo $is_selected; ?>><?php echo esc_html($form['name']); ?></option>
         <?php }  ?>
       </select>
diff --git a/tasks/code_sniffer/MailPoet/Sniffs/ControlStructures/ControlSignatureSniff.php b/tasks/code_sniffer/MailPoet/Sniffs/ControlStructures/ControlSignatureSniff.php
index 80ebe23b9b..fc4b5673bd 100644
--- a/tasks/code_sniffer/MailPoet/Sniffs/ControlStructures/ControlSignatureSniff.php
+++ b/tasks/code_sniffer/MailPoet/Sniffs/ControlStructures/ControlSignatureSniff.php
@@ -13,8 +13,8 @@
  * @link      http://pear.php.net/package/PHP_CodeSniffer
  */
 
-if (class_exists('PHP_CodeSniffer_Standards_AbstractPatternSniff', true) === false) {
-    throw new PHP_CodeSniffer_Exception('Class PHP_CodeSniffer_Standards_AbstractPatternSniff not found');
+if (class_exists('PHP_CodeSniffer\Sniffs\AbstractPatternSniff', true) === false) {
+    throw new PHP_CodeSniffer_Exception('Class PHP_CodeSniffer\Sniffs\AbstractPatternSniff not found');
 }
 
 /**
@@ -29,7 +29,7 @@ if (class_exists('PHP_CodeSniffer_Standards_AbstractPatternSniff', true) === fal
  * @version   Release: @package_version@
  * @link      http://pear.php.net/package/PHP_CodeSniffer
  */
-class MailPoet_Sniffs_ControlStructures_ControlSignatureSniff extends PHP_CodeSniffer_Standards_AbstractPatternSniff {
+class MailPoet_Sniffs_ControlStructures_ControlSignatureSniff extends PHP_CodeSniffer\Sniffs\AbstractPatternSniff {
 
     /**
      * If true, comments will be ignored if they are found in the code.
diff --git a/tasks/code_sniffer/MailPoet/ruleset.xml b/tasks/code_sniffer/MailPoet/ruleset.xml
index 3bc4198bd1..5b94f33acd 100644
--- a/tasks/code_sniffer/MailPoet/ruleset.xml
+++ b/tasks/code_sniffer/MailPoet/ruleset.xml
@@ -1,5 +1,6 @@
 <?xml version="1.0"?>
 <ruleset name="MailPoet">
+  <config name="installed_paths" value="vendor/squizlabs/php_codesniffer,vendor/phpcompatibility/php-compatibility"/>
   <description>MailPoet specific rule set</description>
 
   <!-- Control structures must have at least one statement in the body -->
@@ -118,7 +119,7 @@
   <rule ref="Squiz.Scope.StaticThisUsage"/>
 
   <!-- Remove space between if/for/while and opening parenthesis -->
-  <rule ref="MailPoet.ControlStructures.ControlSignature"/>
+  <rule ref="MailPoet.ControlStructures.ControlSignature" />
 
   <!-- Run against the PHPCompatibility ruleset -->
   <rule ref="PHPCompatibility" />