diff --git a/RoboFile.php b/RoboFile.php
index 5c2f8f9878..958829b03d 100644
--- a/RoboFile.php
+++ b/RoboFile.php
@@ -381,9 +381,9 @@ class RoboFile extends \Robo\Tasks {
 
     return $this->collectionBuilder()
 
-      // PHP >= 5.6 for lib & tests
+      // PHP >= 7.0 for lib & tests
       ->taskExec($task)
-      ->rawArg('--runtime-set testVersion 5.6-7.3')
+      ->rawArg('--runtime-set testVersion 7.0-7.4')
       ->arg('--ignore=' . implode(',', [
           'lib/Config/PopulatorData/Templates',
           'tests/_data',
@@ -396,14 +396,14 @@ class RoboFile extends \Robo\Tasks {
         'tests',
       ])
 
-      // PHP >= 5.6 in plugin root directory
+      // PHP >= 7.0 in plugin root directory
       ->taskExec($task)
-      ->rawArg('--runtime-set testVersion 5.6-7.3')
+      ->rawArg('--runtime-set testVersion 7.0-7.4')
       ->rawArg('-l .')
 
       // PHP >= 7.2 for dev tools, etc.
       ->taskExec($task)
-      ->rawArg('--runtime-set testVersion 7.2-7.3')
+      ->rawArg('--runtime-set testVersion 7.2-7.4')
       ->arg('--ignore=' . implode(',', [
           'prefixer/build',
           'prefixer/vendor',
@@ -429,7 +429,7 @@ class RoboFile extends \Robo\Tasks {
         ->taskExec(
           './tasks/code_sniffer/vendor/bin/phpcbf ' .
             '--standard=./tasks/code_sniffer/MailPoet ' .
-            '--runtime-set testVersion 5.6-7.3 ' .
+            '--runtime-set testVersion 7.0-7.4 ' .
             $filePath . ' -n'
         )
         ->run();
diff --git a/composer.json b/composer.json
index d0f52123e7..b2bc84f15a 100644
--- a/composer.json
+++ b/composer.json
@@ -6,7 +6,7 @@
     }
   ],
   "require": {
-    "php": ">=5.6",
+    "php": ">=7.0",
     "mtdowling/cron-expression": "^1.1",
     "soundasleep/html2text": "dev-master",
     "tburry/pquery": "^1.1.1"
@@ -87,7 +87,7 @@
   },
   "config": {
     "platform": {
-      "php": "5.6.30"
+      "php": "7.0.33"
     },
     "sort-packages": true
   }
diff --git a/mailpoet-cron.php b/mailpoet-cron.php
index 505d82a761..c85410990a 100644
--- a/mailpoet-cron.php
+++ b/mailpoet-cron.php
@@ -25,8 +25,8 @@ if (!is_plugin_active('mailpoet/mailpoet.php')) {
 }
 
 // Check for minimum supported PHP version
-if (version_compare(phpversion(), '5.6.0', '<')) {
-  echo 'MailPoet requires PHP version 5.6 or newer (version 7.2 recommended).';
+if (version_compare(phpversion(), '7.0.0', '<')) {
+  echo 'MailPoet requires PHP version 7.0 or newer (version 7.2 recommended).';
   exit(1);
 }
 
diff --git a/mailpoet.php b/mailpoet.php
index 165377d867..5491a7d349 100644
--- a/mailpoet.php
+++ b/mailpoet.php
@@ -39,7 +39,7 @@ if (version_compare(get_bloginfo('version'), '4.6', '<')) {
 }
 
 // Check for minimum supported PHP version
-if (version_compare(phpversion(), '5.6.0', '<')) {
+if (version_compare(phpversion(), '7.0.0', '<')) {
   add_action('admin_notices', 'mailpoet_php_version_notice');
   // deactivate the plugin
   add_action('admin_init', 'mailpoet_deactivate_plugin');
@@ -62,7 +62,7 @@ function mailpoet_php_version_notice() {
   $notice = str_replace(
     '[link]',
     '<a href="https://kb.mailpoet.com/article/152-minimum-requirements-for-mailpoet-3#php_version" target="_blank">',
-    __('MailPoet requires PHP version 5.6 or newer (version 7.2 recommended). Please read our [link]instructions[/link] on how to upgrade your site.', 'mailpoet')
+    __('MailPoet requires PHP version 7.0 or newer (version 7.2 recommended). Please read our [link]instructions[/link] on how to upgrade your site.', 'mailpoet')
   );
   $notice = str_replace('[/link]', '</a>', $notice);
   printf('<div class="error"><p>%1$s</p></div>', $notice);
diff --git a/prefixer/composer.json b/prefixer/composer.json
index c39ea2721f..b1878b67a4 100644
--- a/prefixer/composer.json
+++ b/prefixer/composer.json
@@ -1,6 +1,6 @@
 {
   "require": {
-    "php": ">=5.6",
+    "php": ">=7.0",
     "cerdic/css-tidy": "^1.7",
     "doctrine/common": "2.7.3",
     "doctrine/dbal": "2.5.13",
@@ -32,7 +32,7 @@
   },
   "config": {
     "platform": {
-      "php": "5.6"
+      "php": "7.0.33"
     },
     "sort-packages": true
   }
diff --git a/prefixer/composer.lock b/prefixer/composer.lock
index b45d50b17c..9b171019ca 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": "e56b3eb2d1443ec19f4f57dff7063fb2",
+    "content-hash": "2316a5d00e066a847c812d348bd0e99e",
     "packages": [
         {
             "name": "cerdic/css-tidy",
@@ -1738,10 +1738,10 @@
     "prefer-stable": false,
     "prefer-lowest": false,
     "platform": {
-        "php": ">=5.6"
+        "php": ">=7.0"
     },
     "platform-dev": [],
     "platform-overrides": {
-        "php": "5.6"
+        "php": "7.0.33"
     }
 }