diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 087b6c383a43d7c54bb80e073dd20a61799db592..0b8be586e981e0a935853124e2e9ad5554c86fb0 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -55,6 +55,7 @@ include:
 # Docs at https://git.drupalcode.org/project/gitlab_templates/-/blob/main/includes/include.drupalci.variables.yml
 ################
 variables:
+  _TARGET_CORE: '$CORE_NEXT_MINOR'
   SKIP_ESLINT: '1'
 #   OPT_IN_TEST_NEXT_MAJOR: '1'
 #   _CURL_TEMPLATES_REF: 'main'
@@ -64,6 +65,8 @@ phpunit:
   before_script:
     - |
       echo -e "\e[0Ksection_start:`date +%s`:my_first_section[collapsed=true]\r\e[0KInstall PHP Extension"
+      apt-get update
+      apt-get install -y --no-install-recommends $PHPIZE_DEPS
       pecl install msgpack && docker-php-ext-enable msgpack
       echo -e "\e[0Ksection_end:`date +%s`:my_first_section\r\e[0K"
 
diff --git a/src/Serialization/MessagePack.php b/src/Serialization/MessagePack.php
index 0f1d9df29a20264904b05d069759dec551763a9a..76b0b8110f8444309365376342b87778ec09fc37 100644
--- a/src/Serialization/MessagePack.php
+++ b/src/Serialization/MessagePack.php
@@ -2,12 +2,13 @@
 
 namespace Drupal\msgpack\Serialization;
 
+use Drupal\Component\Serialization\ObjectAwareSerializationInterface;
 use Drupal\Component\Serialization\SerializationInterface;
 
 /**
  * Provides a MessagePack serialization implementation.
  */
-class MessagePack implements SerializationInterface {
+class MessagePack implements SerializationInterface, ObjectAwareSerializationInterface {
 
   /**
    * {@inheritdoc}