diff --git a/composer.json b/composer.json
index e5a377a..d1a0049 100644
--- a/composer.json
+++ b/composer.json
@@ -17,8 +17,8 @@
 	}
 	],
 	"require" : {
-		"php" : ">=7.0",
-		"doctrine/orm" : "~2.4",
+		"php" : ">=7.1",
+		"doctrine/orm" : "~2.7",
 		"mouf/database.dao-interface" : "2.*",
 		"mouf/utils.common.doctrine-annotations-wrapper" : "~1.2",
 		"mouf/database.doctrine-dbal-wrapper" : "~1.1",
@@ -63,4 +63,4 @@
 			]
 		}
 	}
-}
\ No newline at end of file
+}
diff --git a/src/EntityManager.php b/src/EntityManager.php
index ac9cbbd..9a78ac7 100644
--- a/src/EntityManager.php
+++ b/src/EntityManager.php
@@ -247,7 +247,7 @@ public function remove($entityName \$entity)
      *
      * @return $entityName|null
      */
-    public function findUniqueBy(array \$criteria)
+    public function findUniqueBy(array \$criteria) : ?$entityName
     {
         \$result = \$this->findBy(\$criteria);
 
diff --git a/src/Mapping/Driver/MappingDriverChain.php b/src/Mapping/Driver/MappingDriverChain.php
index 77c03e4..6a820ec 100644
--- a/src/Mapping/Driver/MappingDriverChain.php
+++ b/src/Mapping/Driver/MappingDriverChain.php
@@ -1,12 +1,12 @@
 <?php
 namespace Mouf\Doctrine\ORM\Mapping\Driver;
 
-use Doctrine\Common\Persistence\Mapping\Driver\MappingDriver;
+use Doctrine\Persistence\Mapping\Driver\MappingDriver;
 
 /**
  * Extension of MappingDriverChain to play more easily with Mouf instances.
  */
-class MappingDriverChain extends \Doctrine\Common\Persistence\Mapping\Driver\MappingDriverChain {
+class MappingDriverChain extends \Doctrine\Persistence\Mapping\Driver\MappingDriverChain {
 
     /**
      * @param array<string,MappingDriver> $drivers The key is the namespace, the value the driver to use.