diff --git a/composer.json b/composer.json
index f92d022..fc87889 100644
--- a/composer.json
+++ b/composer.json
@@ -25,6 +25,7 @@
     "php": "^7.0",
     "doctrine/common": "^2.0",
     "doctrine/inflector": "^1.0",
+    "symfony/polyfill-php71": "^1.0",
     "zendframework/zend-paginator": "^2.6"
   },
   "require-dev": {
@@ -56,29 +57,28 @@
   "bin": [
   ],
   "config": {
-    "preferred-install": "dist"
+    "preferred-install": "dist",
+    "sort-packages": true
   },
   "scripts": {
-    "php-lint": "php -l src && php -l tests",
+    "phplint": "php -l src && php -l tests",
     "phpcs": "phpcs --standard=PSR2 src tests",
     "phpcs-lint": "php-cs-fixer fix --dry-run --verbose",
     "phpcpd": "phpcpd src",
-    "phpstan": "phpstan analyse --level 1 src tests",
     "phpmd": "phpmd src text unusedcode,naming,design,controversial,codesize",
-    "phpmetrics": "phpmetrics --failure-condition='average.maintainabilityIndex < 50' src",
-    "phpmetrics-report": "phpmetrics --report-html=build/metrics/index.html --offline src",
+    "phpmetrics-report": "phpmetrics --report-html=build/metrics/index.html --report-violations=build/logs/violations.xml --offline src",
+    "phpstan": "phpstan analyse --level 7 src",
     "phpunit": "phpunit",
     "phpunit-coverage": "phpunit --coverage-html build/coverage",
     "phpunit-clover": "phpunit --coverage-clover build/logs/clover.xml",
     "humbug": "humbug",
     "qa": [
-      "@php-lint",
+      "@phplint",
       "@phpcs",
       "@phpcs-lint",
       "@phpcpd",
       "@phpmd",
-      "@phpstan",
-      "@phpmetrics"
+      "@phpstan"
     ],
     "reports": [
       "@phpmetrics-report",
@@ -87,7 +87,7 @@
     "fix": "php-cs-fixer fix --verbose",
     "security": "composer outdated",
     "test": [
-      "@php-lint",
+      "@qa",
       "@phpunit",
       "@humbug"
     ]
diff --git a/src/Repository.php b/src/Repository.php
index a3dc69c..e8551c5 100644
--- a/src/Repository.php
+++ b/src/Repository.php
@@ -130,8 +130,8 @@ public function getNew();
     /**
      * Add objects.
      *
-     * @param object|object[]|\Traversable $objects
-     * @param bool                         $flush
+     * @param object|iterable $objects
+     * @param bool            $flush
      */
     public function add($objects, bool $flush = false);
 
@@ -161,22 +161,22 @@ public function removeOneBy(array $criteria, bool $flush = false);
     /**
      * Remove objects.
      *
-     * @param object|object[]|\Traversable|string|int $objects
-     * @param bool                                    $flush
+     * @param object|iterable|string|int $objects
+     * @param bool                       $flush
      */
     public function remove($objects, bool $flush = false);
 
     /**
      * Refresh objects.
      *
-     * @param object|object[]|\Traversable $objects
+     * @param object|iterable $objects
      */
     public function refresh($objects);
 
     /**
      * Detach objects.
      *
-     * @param object|object[]|\Traversable $objects
+     * @param object|iterable $objects
      */
     public function detach($objects);
 
diff --git a/src/RepositoryTrait.php b/src/RepositoryTrait.php
index 53b8669..0220692 100644
--- a/src/RepositoryTrait.php
+++ b/src/RepositoryTrait.php
@@ -156,8 +156,8 @@ public function setObjectFactory(callable $objectFactory)
     /**
      * Add objects.
      *
-     * @param object|object[]|\Traversable $objects
-     * @param bool                         $flush
+     * @param object|iterable $objects
+     * @param bool            $flush
      *
      * @throws \InvalidArgumentException
      */
@@ -201,14 +201,14 @@ public function removeOneBy(array $criteria, bool $flush = false)
     /**
      * Remove objects.
      *
-     * @param object|object[]|\Traversable|string|int $objects
-     * @param bool                                    $flush
+     * @param object|iterable|string|int $objects
+     * @param bool                       $flush
      *
      * @throws \InvalidArgumentException
      */
     public function remove($objects, bool $flush = false)
     {
-        if (!is_object($objects) && !is_array($objects) && !$objects instanceof \Traversable) {
+        if (!is_object($objects) && !is_iterable($objects)) {
             $objects = $this->find($objects);
         }
 
@@ -218,7 +218,7 @@ public function remove($objects, bool $flush = false)
     /**
      * Refresh objects.
      *
-     * @param object|object[]|\Traversable $objects
+     * @param object|iterable $objects
      *
      * @throws \InvalidArgumentException
      */
@@ -235,7 +235,7 @@ public function refresh($objects)
     /**
      * Detach objects.
      *
-     * @param object|object[]|\Traversable $objects
+     * @param object|iterable $objects
      *
      * @throws \InvalidArgumentException
      */
@@ -362,9 +362,9 @@ protected function callSupportedMethod(string $method, string $fieldName, array
     /**
      * Run manager action.
      *
-     * @param string                       $action
-     * @param object|object[]|\Traversable $objects
-     * @param bool                         $flush
+     * @param string          $action
+     * @param object|iterable $objects
+     * @param bool            $flush
      *
      * @throws \InvalidArgumentException
      */
@@ -372,7 +372,7 @@ protected function runManagerAction(string $action, $objects, bool $flush)
     {
         $manager = $this->getManager();
 
-        if (!$this->isTraversable($objects)) {
+        if (!is_iterable($objects)) {
             $objects = array_filter([$objects]);
         }
 
@@ -390,24 +390,24 @@ protected function runManagerAction(string $action, $objects, bool $flush)
             $manager->$action($object);
         }
 
+        // @codeCoverageIgnoreStart
+        if ($objects instanceof \Traversable) {
+            $objects = iterator_to_array($objects);
+        }
+        // @codeCoverageIgnoreEnd
+
         $this->flushObjects($objects, $flush);
     }
 
     /**
      * Flush managed objects.
      *
-     * @param object|object[]|\Traversable $objects
-     * @param bool                         $flush
+     * @param array $objects
+     * @param bool  $flush
      */
-    protected function flushObjects($objects, bool $flush)
+    protected function flushObjects(array $objects, bool $flush)
     {
         if ($flush || $this->autoFlush) {
-            // @codeCoverageIgnoreStart
-            if ($objects instanceof \Traversable) {
-                $objects = iterator_to_array($objects);
-            }
-            // @codeCoverageIgnoreEnd
-
             $this->getManager()->flush($objects);
         }
     }
@@ -446,16 +446,4 @@ abstract protected function getManager();
      * @return \Doctrine\Common\Persistence\Mapping\ClassMetadata
      */
     abstract protected function getClassMetadata();
-
-    /**
-     * Is traversable.
-     *
-     * @param mixed $object
-     *
-     * @return bool
-     */
-    private function isTraversable($object): bool
-    {
-        return is_array($object) || $object instanceof \Traversable;
-    }
 }