core/modules/hal/hal.services.yml                           | 4 +---
 core/modules/hal/src/Normalizer/FieldItemNormalizer.php     | 8 +++++++-
 core/modules/hal/src/Normalizer/TimestampItemNormalizer.php | 2 ++
 3 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/core/modules/hal/hal.services.yml b/core/modules/hal/hal.services.yml
index b2c898f..66cf5ba 100644
--- a/core/modules/hal/hal.services.yml
+++ b/core/modules/hal/hal.services.yml
@@ -19,9 +19,7 @@ services:
     arguments: ['@entity.manager', '@http_client', '@hal.link_manager', '@module_handler']
   serializer.normalizer.timestamp_item.hal:
    class: Drupal\hal\Normalizer\TimestampItemNormalizer
-   tags:
-     # Priority must be higher than serializer.normalizer.field_item.hal.
-     - { name: normalizer, priority: 20, bc: bc_timestamp_normalizer_unix, bc_config_name: 'serialization.settings' }
+   deprecated: The "%service_id% service is deprecated in 8.5.0, use the serializer.normalizer.timestamp service instead.
   serializer.normalizer.entity.hal:
     class: Drupal\hal\Normalizer\ContentEntityNormalizer
     arguments: ['@hal.link_manager', '@entity.manager', '@module_handler']
diff --git a/core/modules/hal/src/Normalizer/FieldItemNormalizer.php b/core/modules/hal/src/Normalizer/FieldItemNormalizer.php
index 6d10b06..7b5db31 100644
--- a/core/modules/hal/src/Normalizer/FieldItemNormalizer.php
+++ b/core/modules/hal/src/Normalizer/FieldItemNormalizer.php
@@ -93,7 +93,13 @@ protected function normalizedFieldValues(FieldItemInterface $field_item, $format
     // if needed.
     /** @var \Drupal\Core\TypedData\TypedDataInterface $property */
     foreach (TypedDataInternalPropertiesHelper::getNonInternalProperties($field_item) as $property_name => $property) {
-      $normalized[$property_name] = $this->serializer->normalize($property, $format, $context);
+      $normalized_property = $this->serializer->normalize($property, $format, $context);;
+      if (is_array($normalized_property)) {
+        $normalized += $normalized_property;
+      }
+      else {
+        $normalized[$property_name] = $normalized_property;
+      }
     }
 
     if (isset($context['langcode'])) {
diff --git a/core/modules/hal/src/Normalizer/TimestampItemNormalizer.php b/core/modules/hal/src/Normalizer/TimestampItemNormalizer.php
index c389e79..78ec5a3 100644
--- a/core/modules/hal/src/Normalizer/TimestampItemNormalizer.php
+++ b/core/modules/hal/src/Normalizer/TimestampItemNormalizer.php
@@ -8,6 +8,8 @@
 
 /**
  * Converts values for TimestampItem to and from common formats for hal.
+ *
+ * @deprecated in 8.5.0, use \Drupal\serialization\Normalizer\TimestampNormalizer instead.
  */
 class TimestampItemNormalizer extends FieldItemNormalizer {