diff --git a/UPGRADE.md b/UPGRADE.md
index f78883421..5a8985b08 100644
--- a/UPGRADE.md
+++ b/UPGRADE.md
@@ -7,7 +7,6 @@ an ``EntityManagerInterface`` instead.
 If you are extending any of the following classes, then you need to check following
 signatures:
 
-- ``Doctrine\ORM\Id\AbstractIdGenerator#generate(EntityManagerInterface $em, $entity)``
 - ``Doctrine\ORM\Tools\DebugUnitOfWorkListener#dumpIdentityMap(EntityManagerInterface $em)``
 - ``Doctrine\ORM\Mapping\ClassMetadataFactory#setEntityManager(EntityManagerInterface $em)``
 
diff --git a/lib/Doctrine/ORM/Id/AbstractIdGenerator.php b/lib/Doctrine/ORM/Id/AbstractIdGenerator.php
index 1077e9c3b..5ed2872ad 100644
--- a/lib/Doctrine/ORM/Id/AbstractIdGenerator.php
+++ b/lib/Doctrine/ORM/Id/AbstractIdGenerator.php
@@ -19,19 +19,18 @@
 
 namespace Doctrine\ORM\Id;
 
-use Doctrine\ORM\EntityManagerInterface;
+use Doctrine\ORM\EntityManager;
 
 abstract class AbstractIdGenerator
 {
     /**
      * Generates an identifier for an entity.
      *
-     * @param EntityManagerInterface       $em
+     * @param EntityManager|EntityManager $em
      * @param \Doctrine\ORM\Mapping\Entity $entity
-     *
      * @return mixed
      */
-    abstract public function generate(EntityManagerInterface $em, $entity);
+    abstract public function generate(EntityManager $em, $entity);
 
     /**
      * Gets whether this generator is a post-insert generator which means that
diff --git a/lib/Doctrine/ORM/Id/AssignedGenerator.php b/lib/Doctrine/ORM/Id/AssignedGenerator.php
index b2c2333e1..3ad2cbff7 100644
--- a/lib/Doctrine/ORM/Id/AssignedGenerator.php
+++ b/lib/Doctrine/ORM/Id/AssignedGenerator.php
@@ -19,7 +19,7 @@
 
 namespace Doctrine\ORM\Id;
 
-use Doctrine\ORM\EntityManagerInterface;
+use Doctrine\ORM\EntityManager;
 use Doctrine\ORM\ORMException;
 
 /**
@@ -40,7 +40,8 @@ class AssignedGenerator extends AbstractIdGenerator
      *
      * @throws \Doctrine\ORM\ORMException
      */
-    public function generate(EntityManagerInterface $em, $entity)
+    public function generate(
+        EntityManager $em, $entity)
     {
         $class      = $em->getClassMetadata(get_class($entity));
         $idFields   = $class->getIdentifierFieldNames();
diff --git a/lib/Doctrine/ORM/Id/BigIntegerIdentityGenerator.php b/lib/Doctrine/ORM/Id/BigIntegerIdentityGenerator.php
index 0a5c0273d..01d139f48 100644
--- a/lib/Doctrine/ORM/Id/BigIntegerIdentityGenerator.php
+++ b/lib/Doctrine/ORM/Id/BigIntegerIdentityGenerator.php
@@ -19,7 +19,7 @@
 
 namespace Doctrine\ORM\Id;
 
-use Doctrine\ORM\EntityManagerInterface;
+use Doctrine\ORM\EntityManager;
 
 /**
  * Id generator that obtains IDs from special "identity" columns. These are columns
@@ -50,7 +50,7 @@ class BigIntegerIdentityGenerator extends AbstractIdGenerator
     /**
      * {@inheritDoc}
      */
-    public function generate(EntityManagerInterface $em, $entity)
+    public function generate(EntityManager $em, $entity)
     {
         return (string) $em->getConnection()->lastInsertId($this->sequenceName);
     }
diff --git a/lib/Doctrine/ORM/Id/IdentityGenerator.php b/lib/Doctrine/ORM/Id/IdentityGenerator.php
index a026f4a02..46cd7dbcd 100644
--- a/lib/Doctrine/ORM/Id/IdentityGenerator.php
+++ b/lib/Doctrine/ORM/Id/IdentityGenerator.php
@@ -19,7 +19,7 @@
 
 namespace Doctrine\ORM\Id;
 
-use Doctrine\ORM\EntityManagerInterface;
+use Doctrine\ORM\EntityManager;
 
 /**
  * Id generator that obtains IDs from special "identity" columns. These are columns
@@ -50,7 +50,8 @@ class IdentityGenerator extends AbstractIdGenerator
     /**
      * {@inheritDoc}
      */
-    public function generate(EntityManagerInterface $em, $entity)
+    public function generate(
+        EntityManager $em, $entity)
     {
         return (int)$em->getConnection()->lastInsertId($this->sequenceName);
     }
diff --git a/lib/Doctrine/ORM/Id/SequenceGenerator.php b/lib/Doctrine/ORM/Id/SequenceGenerator.php
index b71a3409f..1236d95b5 100644
--- a/lib/Doctrine/ORM/Id/SequenceGenerator.php
+++ b/lib/Doctrine/ORM/Id/SequenceGenerator.php
@@ -19,7 +19,7 @@
 
 namespace Doctrine\ORM\Id;
 
-use Doctrine\ORM\EntityManagerInterface;
+use Doctrine\ORM\EntityManager;
 use Serializable;
 
 /**
@@ -69,7 +69,7 @@ class SequenceGenerator extends AbstractIdGenerator implements Serializable
     /**
      * {@inheritDoc}
      */
-    public function generate(EntityManagerInterface $em, $entity)
+    public function generate(EntityManager $em, $entity)
     {
         if ($this->_maxValue === null || $this->_nextValue == $this->_maxValue) {
             // Allocate new values
diff --git a/lib/Doctrine/ORM/Id/TableGenerator.php b/lib/Doctrine/ORM/Id/TableGenerator.php
index 809423285..abf3ab8ac 100644
--- a/lib/Doctrine/ORM/Id/TableGenerator.php
+++ b/lib/Doctrine/ORM/Id/TableGenerator.php
@@ -19,7 +19,7 @@
 
 namespace Doctrine\ORM\Id;
 
-use Doctrine\ORM\EntityManagerInterface;
+use Doctrine\ORM\EntityManager;
 
 /**
  * Id generator that uses a single-row database table and a hi/lo algorithm.
@@ -72,7 +72,8 @@ class TableGenerator extends AbstractIdGenerator
     /**
      * {@inheritDoc}
      */
-    public function generate(EntityManagerInterface $em, $entity)
+    public function generate(
+        EntityManager $em, $entity)
     {
         if ($this->_maxValue === null || $this->_nextValue == $this->_maxValue) {
             // Allocate new values
diff --git a/lib/Doctrine/ORM/Id/UuidGenerator.php b/lib/Doctrine/ORM/Id/UuidGenerator.php
index 4287f2b1f..a8e92bbe2 100644
--- a/lib/Doctrine/ORM/Id/UuidGenerator.php
+++ b/lib/Doctrine/ORM/Id/UuidGenerator.php
@@ -19,7 +19,7 @@
 
 namespace Doctrine\ORM\Id;
 
-use Doctrine\ORM\EntityManagerInterface;
+use Doctrine\ORM\EntityManager;
 
 /**
  * Represents an ID generator that uses the database UUID expression
@@ -32,7 +32,7 @@ class UuidGenerator extends AbstractIdGenerator
     /**
      * {@inheritDoc}
      */
-    public function generate(EntityManagerInterface $em, $entity)
+    public function generate(EntityManager $em, $entity)
     {
         $conn = $em->getConnection();
         $sql = 'SELECT ' . $conn->getDatabasePlatform()->getGuidExpression();
diff --git a/tests/Doctrine/Tests/Mocks/SequenceMock.php b/tests/Doctrine/Tests/Mocks/SequenceMock.php
index db73051d2..4f5123004 100644
--- a/tests/Doctrine/Tests/Mocks/SequenceMock.php
+++ b/tests/Doctrine/Tests/Mocks/SequenceMock.php
@@ -2,7 +2,7 @@
 
 namespace Doctrine\Tests\Mocks;
 
-use Doctrine\ORM\EntityManagerInterface;
+use Doctrine\ORM\EntityManager;
 
 /**
  * Mock class for SequenceGenerator.
@@ -17,7 +17,7 @@ class SequenceMock extends \Doctrine\ORM\Id\SequenceGenerator
     /**
      * {@inheritdoc}
      */
-    public function generate(EntityManagerInterface $em, $entity)
+    public function generate(EntityManager $em, $entity)
     {
         return $this->_sequenceNumber++;
     }
diff --git a/tests/Doctrine/Tests/ORM/Functional/Ticket/DDC2415Test.php b/tests/Doctrine/Tests/ORM/Functional/Ticket/DDC2415Test.php
index a55eba14e..0283e6457 100644
--- a/tests/Doctrine/Tests/ORM/Functional/Ticket/DDC2415Test.php
+++ b/tests/Doctrine/Tests/ORM/Functional/Ticket/DDC2415Test.php
@@ -2,7 +2,7 @@
 
 namespace Doctrine\Tests\ORM\Functional\Ticket;
 
-use Doctrine\ORM\EntityManagerInterface;
+use Doctrine\ORM\EntityManager;
 use Doctrine\ORM\Id\AbstractIdGenerator;
 use Doctrine\ORM\Mapping\ClassMetadataInfo;
 use Doctrine\ORM\Mapping\Driver\StaticPHPDriver;
@@ -97,7 +97,7 @@ class DDC2415ChildEntity extends DDC2415ParentEntity
 
 class DDC2415Generator extends AbstractIdGenerator
 {
-    public function generate(EntityManagerInterface $em, $entity)
+    public function generate(EntityManager $em, $entity)
     {
         return md5($entity->getName());
     }
diff --git a/tests/Doctrine/Tests/ORM/Mapping/ClassMetadataFactoryTest.php b/tests/Doctrine/Tests/ORM/Mapping/ClassMetadataFactoryTest.php
index 394b737a5..31345fdcc 100644
--- a/tests/Doctrine/Tests/ORM/Mapping/ClassMetadataFactoryTest.php
+++ b/tests/Doctrine/Tests/ORM/Mapping/ClassMetadataFactoryTest.php
@@ -2,17 +2,17 @@
 
 namespace Doctrine\Tests\ORM\Mapping;
 
+use Doctrine\Common\EventManager;
+use Doctrine\ORM\EntityManager;
 use Doctrine\ORM\Event\OnClassMetadataNotFoundEventArgs;
 use Doctrine\ORM\Events;
-use Doctrine\Tests\Mocks\MetadataDriverMock;
-use Doctrine\Tests\Mocks\EntityManagerMock;
+use Doctrine\ORM\Id\AbstractIdGenerator;
+use Doctrine\ORM\Mapping\ClassMetadata;
+use Doctrine\ORM\Mapping\ClassMetadataFactory;
 use Doctrine\Tests\Mocks\ConnectionMock;
 use Doctrine\Tests\Mocks\DriverMock;
-use Doctrine\ORM\Mapping\ClassMetadata;
-use Doctrine\Common\EventManager;
-use Doctrine\ORM\EntityManagerInterface;
-use Doctrine\ORM\Id\AbstractIdGenerator;
-use Doctrine\ORM\Mapping\ClassMetadataFactory;
+use Doctrine\Tests\Mocks\EntityManagerMock;
+use Doctrine\Tests\Mocks\MetadataDriverMock;
 
 class ClassMetadataFactoryTest extends \Doctrine\Tests\OrmTestCase
 {
@@ -367,7 +367,7 @@ class ClassMetadataFactoryTest extends \Doctrine\Tests\OrmTestCase
     {
         $classMetadataFactory = new ClassMetadataFactory();
 
-        /* @var $entityManager \Doctrine\ORM\EntityManager */
+        /* @var $entityManager EntityManager */
         $entityManager        = $this->getMock('Doctrine\\ORM\\EntityManagerInterface');
 
         $classMetadataFactory->setEntityManager($entityManager);
@@ -414,7 +414,7 @@ class TestEntity1
 
 class CustomIdGenerator extends AbstractIdGenerator
 {
-    public function generate(EntityManagerInterface $em, $entity)
+    public function generate(EntityManager $em, $entity)
     {
     }
 }