diff --git a/akka-remote/src/main/scala/akka/remote/serialization/ProtobufSerializer.scala b/akka-remote/src/main/scala/akka/remote/serialization/ProtobufSerializer.scala
index 01e7ee8fa0..ac8e758383 100644
--- a/akka-remote/src/main/scala/akka/remote/serialization/ProtobufSerializer.scala
+++ b/akka-remote/src/main/scala/akka/remote/serialization/ProtobufSerializer.scala
@@ -40,9 +40,6 @@ object ProtobufSerializer {
  */
 class ProtobufSerializer(val system: ExtendedActorSystem) extends BaseSerializer {
 
-  @deprecated("Will be removed without replacement", "2.4")
-  val ARRAY_OF_BYTE_ARRAY = Array[Class[_]](classOf[Array[Byte]])
-
   private val parsingMethodBindingRef = new AtomicReference[Map[Class[_], Method]](Map.empty)
   private val toByteArrayMethodBindingRef = new AtomicReference[Map[Class[_], Method]](Map.empty)
 
diff --git a/project/MiMa.scala b/project/MiMa.scala
index aaffcbb3e4..08584d0d67 100644
--- a/project/MiMa.scala
+++ b/project/MiMa.scala
@@ -305,6 +305,9 @@ object MiMa extends AutoPlugin {
       ProblemFilters.exclude[IncompatibleMethTypeProblem]("akka.cluster.sharding.PersistentShardCoordinator.persistAsync"),
       ProblemFilters.exclude[IncompatibleMethTypeProblem]("akka.cluster.sharding.RemoveInternalClusterShardingData#RemoveOnePersistenceId.persist"),
       ProblemFilters.exclude[IncompatibleMethTypeProblem]("akka.cluster.sharding.RemoveInternalClusterShardingData#RemoveOnePersistenceId.persistAsync"),
+      
+      // #21423 remove deprecated ARRAY_OF_BYTE_ARRAY
+      ProblemFilters.exclude[DirectMissingMethodProblem]("akka.remote.serialization.ProtobufSerializer.ARRAY_OF_BYTE_ARRAY"),
           
       // #21423 removal of deprecated `PersistentView` (in 2.5.x)
       ProblemFilters.exclude[MissingClassProblem]("akka.persistence.Update"),