diff --git a/akka-cluster/src/main/scala/akka/cluster/ClusterEvent.scala b/akka-cluster/src/main/scala/akka/cluster/ClusterEvent.scala
index 181ee76774..18ad6853c6 100644
--- a/akka-cluster/src/main/scala/akka/cluster/ClusterEvent.scala
+++ b/akka-cluster/src/main/scala/akka/cluster/ClusterEvent.scala
@@ -5,7 +5,7 @@ package akka.cluster
 
 import language.postfixOps
 import scala.collection.immutable
-import scala.collection.immutable.VectorBuilder
+import scala.collection.immutable.{ SortedSet, VectorBuilder }
 import akka.actor.{ Actor, ActorLogging, ActorRef, Address }
 import akka.cluster.ClusterSettings.DataCenter
 import akka.cluster.ClusterEvent._
@@ -16,6 +16,7 @@ import akka.actor.DeadLetterSuppression
 import akka.annotation.InternalApi
 
 import scala.collection.breakOut
+import scala.runtime.AbstractFunction5
 
 /**
  * Domain events published to the event bus.
@@ -55,17 +56,52 @@ object ClusterEvent {
    */
   sealed trait ClusterDomainEvent extends DeadLetterSuppression
 
+  // for binary compatibility (used to be a case class)
+  object CurrentClusterState extends AbstractFunction5[immutable.SortedSet[Member], Set[Member], Set[Address], Option[Address], Map[String, Option[Address]], CurrentClusterState] {
+
+    def apply(
+      members:       immutable.SortedSet[Member]  = immutable.SortedSet.empty,
+      unreachable:   Set[Member]                  = Set.empty,
+      seenBy:        Set[Address]                 = Set.empty,
+      leader:        Option[Address]              = None,
+      roleLeaderMap: Map[String, Option[Address]] = Map.empty): CurrentClusterState =
+      new CurrentClusterState(members, unreachable, seenBy, leader, roleLeaderMap)
+
+    def unapply(cs: CurrentClusterState): Option[(immutable.SortedSet[Member], Set[Member], Set[Address], Option[Address], Map[String, Option[Address]])] =
+      Some((
+        cs.members,
+        cs.unreachable,
+        cs.seenBy,
+        cs.leader,
+        cs.roleLeaderMap
+      ))
+
+  }
+
   /**
    * Current snapshot state of the cluster. Sent to new subscriber.
    *
    * @param leader leader of the data center of this node
    */
-  final case class CurrentClusterState(
-    members:       immutable.SortedSet[Member]  = immutable.SortedSet.empty,
-    unreachable:   Set[Member]                  = Set.empty,
-    seenBy:        Set[Address]                 = Set.empty,
-    leader:        Option[Address]              = None,
-    roleLeaderMap: Map[String, Option[Address]] = Map.empty) {
+  @SerialVersionUID(2)
+  final class CurrentClusterState(
+    val members:                immutable.SortedSet[Member],
+    val unreachable:            Set[Member],
+    val seenBy:                 Set[Address],
+    val leader:                 Option[Address],
+    val roleLeaderMap:          Map[String, Option[Address]],
+    val unreachableDataCenters: Set[DataCenter])
+    extends Product5[immutable.SortedSet[Member], Set[Member], Set[Address], Option[Address], Map[String, Option[Address]]]
+    with Serializable {
+
+    // for binary compatibility
+    def this(
+      members:       immutable.SortedSet[Member]  = immutable.SortedSet.empty,
+      unreachable:   Set[Member]                  = Set.empty,
+      seenBy:        Set[Address]                 = Set.empty,
+      leader:        Option[Address]              = None,
+      roleLeaderMap: Map[String, Option[Address]] = Map.empty) =
+      this(members, unreachable, seenBy, leader, roleLeaderMap, Set.empty)
 
     /**
      * Java API: get current member list.
@@ -125,6 +161,47 @@ object ClusterEvent {
     def getAllDataCenters: java.util.Set[String] =
       scala.collection.JavaConverters.setAsJavaSetConverter(allDataCenters).asJava
 
+    /**
+     * Replace the set of unreachable datacenters with the given set
+     */
+    def withUnreachableDataCenters(unreachableDataCenters: Set[DataCenter]): CurrentClusterState =
+      new CurrentClusterState(members, unreachable, seenBy, leader, roleLeaderMap, unreachableDataCenters)
+
+    // for binary compatibility (used to be a case class)
+    def copy(
+      members:       immutable.SortedSet[Member]  = this.members,
+      unreachable:   Set[Member]                  = this.unreachable,
+      seenBy:        Set[Address]                 = this.seenBy,
+      leader:        Option[Address]              = this.leader,
+      roleLeaderMap: Map[String, Option[Address]] = this.roleLeaderMap) =
+      new CurrentClusterState(members, unreachable, seenBy, leader, roleLeaderMap, unreachableDataCenters)
+
+    override def equals(other: Any): Boolean = other match {
+      case that: CurrentClusterState ⇒
+        (this eq that) || (
+          members == that.members &&
+          unreachable == that.unreachable &&
+          seenBy == that.seenBy &&
+          leader == that.leader &&
+          roleLeaderMap == that.roleLeaderMap)
+      case _ ⇒ false
+    }
+
+    override def hashCode(): Int = {
+      val state = Seq(members, unreachable, seenBy, leader, roleLeaderMap)
+      state.map(_.hashCode()).foldLeft(0)((a, b) ⇒ 31 * a + b)
+    }
+
+    // Product5
+    override def productPrefix = "CurrentClusterState"
+    def _1: SortedSet[Member] = members
+    def _2: Set[Member] = unreachable
+    def _3: Set[Address] = seenBy
+    def _4: Option[Address] = leader
+    def _5: Map[String, Option[Address]] = roleLeaderMap
+    def canEqual(that: Any): Boolean = that.isInstanceOf[CurrentClusterState]
+
+    override def toString = s"CurrentClusterState($members, $unreachable, $seenBy, $leader, $roleLeaderMap)"
   }
 
   /**
@@ -305,7 +382,10 @@ object ClusterEvent {
       }(collection.breakOut)
     }
 
-  private def isReachable(state: MembershipState, oldUnreachableNodes: Set[UniqueAddress])(otherDc: DataCenter): Boolean = {
+  /**
+   * Internal API
+   */
+  private[cluster] def isReachable(state: MembershipState, oldUnreachableNodes: Set[UniqueAddress])(otherDc: DataCenter): Boolean = {
     val unrelatedDcNodes = state.latestGossip.members.collect {
       case m if m.dataCenter != otherDc && m.dataCenter != state.selfDc ⇒ m.uniqueAddress
     }
@@ -464,13 +544,20 @@ private[cluster] final class ClusterDomainEventPublisher extends Actor with Acto
       membershipState.dcReachabilityNoOutsideNodes.allUnreachableOrTerminated.collect {
         case node if node != selfUniqueAddress ⇒ membershipState.latestGossip.member(node)
       }
-    val state = CurrentClusterState(
+
+    val unreachableDataCenters: Set[DataCenter] =
+      if (!membershipState.latestGossip.isMultiDc) Set.empty
+      else membershipState.latestGossip.allDataCenters.filterNot(isReachable(membershipState, Set.empty))
+
+    val state = new CurrentClusterState(
       members = membershipState.latestGossip.members,
       unreachable = unreachable,
       seenBy = membershipState.latestGossip.seenBy.map(_.address),
       leader = membershipState.leader.map(_.address),
       roleLeaderMap = membershipState.latestGossip.allRoles.map(r ⇒
-        r → membershipState.roleLeader(r).map(_.address))(collection.breakOut))
+        r → membershipState.roleLeader(r).map(_.address))(collection.breakOut),
+      unreachableDataCenters
+    )
     receiver ! state
   }
 
diff --git a/akka-cluster/src/main/scala/akka/cluster/ClusterReadView.scala b/akka-cluster/src/main/scala/akka/cluster/ClusterReadView.scala
index 20799cfb11..40b32777de 100644
--- a/akka-cluster/src/main/scala/akka/cluster/ClusterReadView.scala
+++ b/akka-cluster/src/main/scala/akka/cluster/ClusterReadView.scala
@@ -70,6 +70,12 @@ private[akka] class ClusterReadView(cluster: Cluster) extends Closeable {
             _state = _state.copy(roleLeaderMap = _state.roleLeaderMap + (role → leader))
           case stats: CurrentInternalStats ⇒ _latestStats = stats
           case ClusterShuttingDown         ⇒
+
+          case r: ReachableDataCenter ⇒
+            _state = _state.withUnreachableDataCenters(_state.unreachableDataCenters - r.dataCenter)
+          case r: UnreachableDataCenter ⇒
+            _state = _state.withUnreachableDataCenters(_state.unreachableDataCenters + r.dataCenter)
+
         }
         case s: CurrentClusterState ⇒ _state = s
       }