diff --git a/.travis.yml b/.travis.yml
index 4490198..0adb894 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -33,6 +33,7 @@ services:
 install: make install
 
 script:
+  - make cgl
   - make unitTests
   - make functionalTests
 
diff --git a/Classes/Connection/Elasticsearch.php b/Classes/Connection/Elasticsearch.php
index 8a3cb2b..b86bebf 100644
--- a/Classes/Connection/Elasticsearch.php
+++ b/Classes/Connection/Elasticsearch.php
@@ -132,7 +132,10 @@ class Elasticsearch implements Singleton, ConnectionInterface
                 }
             );
         } catch (\Elastica\Exception\NotFoundException $exception) {
-            $this->logger->debug('Tried to delete document in index, which does not exist.', [$documentType, $identifier]);
+            $this->logger->debug(
+                'Tried to delete document in index, which does not exist.',
+                [$documentType, $identifier]
+            );
         }
     }
 
diff --git a/Classes/Domain/Index/TcaIndexer/TcaTableService.php b/Classes/Domain/Index/TcaIndexer/TcaTableService.php
index 7a322a0..bf631b1 100644
--- a/Classes/Domain/Index/TcaIndexer/TcaTableService.php
+++ b/Classes/Domain/Index/TcaIndexer/TcaTableService.php
@@ -159,7 +159,9 @@ class TcaTableService
         $parameters = [];
         $whereClause = $this->getSystemWhereClause();
 
-        $userDefinedWhere = $this->configuration->getIfExists('indexing.' . $this->getTableName() . '.additionalWhereClause');
+        $userDefinedWhere = $this->configuration->getIfExists(
+            'indexing.' . $this->getTableName() . '.additionalWhereClause'
+        );
         if (is_string($userDefinedWhere)) {
             $whereClause .= ' AND ' . $userDefinedWhere;
         }
@@ -361,6 +363,9 @@ class TcaTableService
      */
     protected function getBlackListedRootLine() : array
     {
-        return GeneralUtility::intExplode(',', $this->configuration->getIfExists('indexing.' . $this->getTableName() . '.rootLineBlacklist'));
+        return GeneralUtility::intExplode(
+            ',',
+            $this->configuration->getIfExists('indexing.' . $this->getTableName() . '.rootLineBlacklist')
+        );
     }
 }
diff --git a/Classes/Domain/Search/QueryFactory.php b/Classes/Domain/Search/QueryFactory.php
index f73372d..5879b9f 100644
--- a/Classes/Domain/Search/QueryFactory.php
+++ b/Classes/Domain/Search/QueryFactory.php
@@ -163,7 +163,11 @@ class QueryFactory
     {
         try {
             $query = ArrayUtility::arrayMergeRecursiveOverrule($query, [
-                'stored_fields' => GeneralUtility::trimExplode(',', $this->configuration->get('searching.fields.stored_fields'), true),
+                'stored_fields' => GeneralUtility::trimExplode(
+                    ',',
+                    $this->configuration->get('searching.fields.stored_fields'),
+                    true
+                ),
             ]);
         } catch (InvalidArgumentException $e) {
             // Nothing configured
@@ -171,7 +175,10 @@ class QueryFactory
 
         try {
             $scriptFields = $this->configuration->get('searching.fields.script_fields');
-            $scriptFields = $this->configurationUtility->replaceArrayValuesWithRequestContent($searchRequest, $scriptFields);
+            $scriptFields = $this->configurationUtility->replaceArrayValuesWithRequestContent(
+                $searchRequest,
+                $scriptFields
+            );
             $scriptFields = $this->configurationUtility->filterByCondition($scriptFields);
             if ($scriptFields !== []) {
                 $query = ArrayUtility::arrayMergeRecursiveOverrule($query, ['script_fields' => $scriptFields]);
diff --git a/Classes/Hook/DataHandler.php b/Classes/Hook/DataHandler.php
index d0eb1ba..0caac7c 100644
--- a/Classes/Hook/DataHandler.php
+++ b/Classes/Hook/DataHandler.php
@@ -103,8 +103,13 @@ class DataHandler implements Singleton
      *
      * @return bool False if hook was not processed.
      */
-    public function processDatamap_afterDatabaseOperations($status, $table, $uid, array $fieldArray, CoreDataHandler $dataHandler)
-    {
+    public function processDatamap_afterDatabaseOperations(
+        $status,
+        $table,
+        $uid,
+        array $fieldArray,
+        CoreDataHandler $dataHandler
+    ) {
         if (! $this->shouldProcessHookForTable($table)) {
             $this->logger->debug('Database update not processed.', [$table, $uid]);
             return false;
diff --git a/Makefile b/Makefile
index b6bc72b..b8f4ac5 100644
--- a/Makefile
+++ b/Makefile
@@ -12,9 +12,12 @@ typo3DatabaseHost ?= "127.0.0.1"
 
 .PHONY: install
 install: clean
-	COMPOSER_PROCESS_TIMEOUT=1000 composer require -vv --dev --prefer-dist --ignore-platform-reqs typo3/cms="$(TYPO3_VERSION)"
+	COMPOSER_PROCESS_TIMEOUT=1000 composer require -vv --dev --prefer-dist typo3/cms="$(TYPO3_VERSION)"
 	git checkout composer.json
 
+cgl:
+	./.Build/bin/phpcs
+
 functionalTests:
 	typo3DatabaseName=$(typo3DatabaseName) \
 		typo3DatabaseUsername=$(typo3DatabaseUsername) \
diff --git a/Tests/Unit/Configuration/ConfigurationUtilityTest.php b/Tests/Unit/Configuration/ConfigurationUtilityTest.php
index b2dc5f8..4db367c 100644
--- a/Tests/Unit/Configuration/ConfigurationUtilityTest.php
+++ b/Tests/Unit/Configuration/ConfigurationUtilityTest.php
@@ -31,8 +31,11 @@ class ConfigurationUtilityTest extends AbstractUnitTestCase
      * @test
      * @dataProvider possibleRequestAndConfigurationForFluidtemplate
      */
-    public function recursiveEntriesAreProcessedAsFluidtemplate(SearchRequestInterface $searchRequest, array $array, array $expected)
-    {
+    public function recursiveEntriesAreProcessedAsFluidtemplate(
+        SearchRequestInterface $searchRequest,
+        array $array,
+        array $expected
+    ) {
         $subject = new ConfigurationUtility();
 
         $this->assertSame(
diff --git a/Tests/Unit/Domain/Search/QueryFactoryTest.php b/Tests/Unit/Domain/Search/QueryFactoryTest.php
index 6301cdd..218f8e5 100644
--- a/Tests/Unit/Domain/Search/QueryFactoryTest.php
+++ b/Tests/Unit/Domain/Search/QueryFactoryTest.php
@@ -465,7 +465,6 @@ class QueryFactoryTest extends AbstractUnitTestCase
             $query->toArray()['script_fields'],
             'Script fields were not added to query as expected.'
         );
-
     }
 
     /**
diff --git a/composer.json b/composer.json
index 985be01..efa5146 100644
--- a/composer.json
+++ b/composer.json
@@ -16,13 +16,13 @@
         }
     },
     "require" : {
-        "php": ">=7.1.0",
-        "typo3/cms": "~8.7",
+        "php": ">=5.6.0",
         "ruflin/elastica": "~3.2"
     },
     "require-dev": {
-        "typo3/testing-framework": "~1.1.0",
-        "phpunit/phpunit": "~6.2.0"
+        "phpunit/phpunit": "~5.7.0",
+        "squizlabs/php_codesniffer": "~3.1.1",
+        "typo3/cms": "~7.6"
     },
     "config": {
         "optimize-autoloader": true,
@@ -36,9 +36,6 @@
         ]
     },
     "extra": {
-        "branch-alias": {
-            "dev-develop": "1.0.x-dev"
-        },
         "typo3/cms": {
             "cms-package-dir": "{$vendor-dir}/typo3/cms",
             "web-dir": ".Build/web"
diff --git a/phpcs.xml.dist b/phpcs.xml.dist
new file mode 100644
index 0000000..e722968
--- /dev/null
+++ b/phpcs.xml.dist
@@ -0,0 +1,23 @@
+<?xml version="1.0"?>
+<ruleset name="search_core">
+    <description>The coding standard for search_core.</description>
+
+    <file>Classes/</file>
+    <file>Tests/</file>
+
+    <!-- Set default settings -->
+    <arg value="sp"/>
+    <arg name="colors"/>
+    <arg name="encoding" value="utf-8" />
+    <arg name="extensions" value="php,php.dist,inc" />
+
+    <!-- Base rules -->
+    <rule ref="PSR2">
+        <!-- As it does not work with new array syntax. -->
+        <exclude name="Squiz.Arrays.ArrayBracketSpacing.SpaceBeforeBracket" />
+    </rule>
+    <rule ref="PSR1.Methods.CamelCapsMethodName.NotCamelCaps">
+        <!-- We have to follow the TYPO3 hook method names. -->
+        <exclude-pattern>Classes/Hook/DataHandler.php</exclude-pattern>
+    </rule>
+</ruleset>