diff --git a/.circleci/config.yml b/.circleci/config.yml
index 9f5f8dfcb..5a12b99fd 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -32,7 +32,7 @@ jobs:
           keys:
             - composer-v2-{{ checksum "composer.json" }}
             - composer-v2-
-      - run: php -d memory_limit=2G /usr/local/bin/composer install -n --prefer-dist
+      - run: php -d memory_limit=-1 /usr/local/bin/composer install -n --prefer-dist
       - save_cache:
           key: composer-v2-{{ checksum "composer.json" }}
           paths:
diff --git a/.travis.yml b/.travis.yml
index e802cce90..f299ed3a1 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -22,7 +22,7 @@ matrix:
         - ES_VERSION="2.4.4"
         - ES_DOWNLOAD_URL="https://download.elastic.co/elasticsearch/elasticsearch/elasticsearch-${ES_VERSION}.zip"
         - ENABLE_SWAP=true
-    - php: 7.2
+    - php: 7.3
       env:
         - COMPOSER_FLAGS="--prefer-dist --no-interaction"
         - SYMFONY__PHPCR__TRANSPORT=jackrabbit
diff --git a/Document/Form/ArticleDocumentType.php b/Document/Form/ArticleDocumentType.php
index 0b42d8834..6f97fc5f4 100644
--- a/Document/Form/ArticleDocumentType.php
+++ b/Document/Form/ArticleDocumentType.php
@@ -34,7 +34,7 @@ public function buildForm(FormBuilderInterface $builder, array $options)
         parent::buildForm($builder, $options);
 
         // extensions
-        $builder->add('extensions', TextType::class, ['property_path' => 'extensionsData']);
+        $builder->add('extensions', UnstructuredType::class, ['property_path' => 'extensionsData']);
         $builder->add('shadowLocaleEnabled', CheckboxType::class);
         $builder->add('shadowLocale', TextType::class);
         $builder->add('mainWebspace', TextType::class);
diff --git a/Document/Form/UnstructuredType.php b/Document/Form/UnstructuredType.php
new file mode 100644
index 000000000..a69251297
--- /dev/null
+++ b/Document/Form/UnstructuredType.php
@@ -0,0 +1,32 @@
+<?php
+
+/*
+ * This file is part of Sulu.
+ *
+ * (c) MASSIVE ART WebServices GmbH
+ *
+ * This source file is subject to the MIT license that is bundled
+ * with this source code in the file LICENSE.
+ */
+
+namespace Sulu\Bundle\ArticleBundle\Document\Form;
+
+use Symfony\Component\Form\AbstractType;
+use Symfony\Component\OptionsResolver\OptionsResolver;
+
+/**
+ * @internal
+ */
+class UnstructuredType extends AbstractType
+{
+    /**
+     * {@inheritdoc}
+     */
+    public function configureOptions(OptionsResolver $resolver)
+    {
+        $resolver->setDefaults([
+            'compound' => false,
+            'multiple' => true,
+        ]);
+    }
+}
diff --git a/composer.json b/composer.json
index efc26200d..4d15f23c1 100644
--- a/composer.json
+++ b/composer.json
@@ -21,7 +21,8 @@
         "phpunit/phpunit": "^4.8 || ^5.0",
         "sulu/automation-bundle": "^1.2",
         "php-task/task-bundle": "^1.2",
-        "php-task/php-task": "^1.2"
+        "php-task/php-task": "^1.2",
+        "doctrine/data-fixtures": "^1.0"
     },
     "suggest": {
         "sulu/automation-bundle": "Allows to outsource long-running route update processes."