diff --git a/core/lib/Drupal/Core/Entity/EntityType.php b/core/lib/Drupal/Core/Entity/EntityType.php
index 491437f..fa1c6d0 100644
--- a/core/lib/Drupal/Core/Entity/EntityType.php
+++ b/core/lib/Drupal/Core/Entity/EntityType.php
@@ -14,6 +14,11 @@
  */
 class EntityType implements EntityTypeInterface {
 
+  /*
+   * Defines EntityChangedInterface constant for internal usage
+   */
+  const ENTITY_TYPE_ENTITY_CHANGED_INTERFACE = 'Drupal\Core\Entity\EntityChangedInterface';
+  
   use StringTranslationTrait;
 
   /**
@@ -301,7 +306,7 @@ public function __construct($definition) {
 
     // Automatically add the EntityChanged constraint if the entity type tracks
     // the changed time.
-    if (is_subclass_of($this->getClass(), 'Drupal\Core\Entity\EntityChangedInterface')) {
+    if (is_subclass_of($this->getClass(), self::ENTITY_TYPE_ENTITY_CHANGED_INTERFACE)) {
       $this->addConstraint('EntityChanged');
     }
 
diff --git a/core/lib/Drupal/Core/Entity/EntityTypeInterface.php b/core/lib/Drupal/Core/Entity/EntityTypeInterface.php
index e991105..7011f28 100644
--- a/core/lib/Drupal/Core/Entity/EntityTypeInterface.php
+++ b/core/lib/Drupal/Core/Entity/EntityTypeInterface.php
@@ -360,7 +360,7 @@ public function setAccessClass($class);
    * @return bool
    *   TRUE if the entity type is a subclass of the class or interface.
    *
-   * @deprecated in Drupal 8.0.x-dev, will be removed before Drupal 8.0.0
+   * @deprecated in Drupal 8.0.x-dev, will be removed before Drupal 9.0.0
    */
   public function isSubclassOf($class);