diff --git a/core/modules/jsonld/lib/Drupal/jsonld/JsonldEntityNormalizer.php b/core/modules/jsonld/lib/Drupal/jsonld/JsonldEntityNormalizer.php
index 5b2c5bf81c645da4478a9e2d796523cfa9da0eb0..b85941b29e192993ba7316aac0b2f5c951cfcab8 100644
--- a/core/modules/jsonld/lib/Drupal/jsonld/JsonldEntityNormalizer.php
+++ b/core/modules/jsonld/lib/Drupal/jsonld/JsonldEntityNormalizer.php
@@ -31,6 +31,8 @@ public function normalize($entity, $format = NULL) {
    * Implements \Symfony\Component\Serializer\Normalizer\NormalizerInterface::supportsNormalization()
    */
   public function supportsNormalization($data, $format = NULL) {
+    // @todo Switch to EntityInterface once all entity types are converted to
+    // EntityNG.
     return parent::supportsNormalization($data, $format) && ($data instanceof EntityNG);
   }
 
diff --git a/core/modules/jsonld/lib/Drupal/jsonld/JsonldFieldItemNormalizer.php b/core/modules/jsonld/lib/Drupal/jsonld/JsonldFieldItemNormalizer.php
index d0c2fdf87eea7c1c6ac0a128c3530cb42ddae9ee..3fac801226c14927e7a24b2b5d65159f35c4777f 100644
--- a/core/modules/jsonld/lib/Drupal/jsonld/JsonldFieldItemNormalizer.php
+++ b/core/modules/jsonld/lib/Drupal/jsonld/JsonldFieldItemNormalizer.php
@@ -7,7 +7,7 @@
 
 namespace Drupal\jsonld;
 
-use Drupal\Core\Entity\Field\FieldItemBase;
+use Drupal\Core\Entity\Field\FieldItemInterface;
 use Drupal\jsonld\JsonldNormalizerBase;
 use Symfony\Component\Serializer\Exception\RuntimeException;
 
@@ -20,14 +20,14 @@ class JsonldFieldItemNormalizer extends JsonldNormalizerBase {
    * Implements \Symfony\Component\Serializer\Normalizer\NormalizerInterface::normalize()
    */
   public function normalize($object, $format = NULL) {
-    return $object->getValue();
+    return $object->getPropertyValues();
   }
 
   /**
    * Implements \Symfony\Component\Serializer\Normalizer\NormalizerInterface::supportsNormalization()
    */
   public function supportsNormalization($data, $format = NULL) {
-    return parent::supportsNormalization($data, $format) && ($data instanceof FieldItemBase);
+    return parent::supportsNormalization($data, $format) && ($data instanceof FieldItemInterface);
   }
 
 }