diff --git a/akka-actor-tests/src/test/scala/akka/actor/ActorSystemSpec.scala b/akka-actor-tests/src/test/scala/akka/actor/ActorSystemSpec.scala
index e8440efe31..9752154e86 100644
--- a/akka-actor-tests/src/test/scala/akka/actor/ActorSystemSpec.scala
+++ b/akka-actor-tests/src/test/scala/akka/actor/ActorSystemSpec.scala
@@ -197,30 +197,26 @@ class ActorSystemSpec extends AkkaSpec(ActorSystemSpec.config) with ImplicitSend
       import system.dispatcher
       system2.scheduler.scheduleOnce(200.millis.dilated) { system2.terminate() }
 
-      system2.awaitTermination(5 seconds)
       Await.ready(system2.whenTerminated, 5 seconds)
       callbackWasRun should ===(true)
     }
 
     "return isTerminated status correctly" in {
       val system = ActorSystem().asInstanceOf[ActorSystemImpl]
-      system.isTerminated should ===(false)
       val wt = system.whenTerminated
       wt.isCompleted should ===(false)
       val f = system.terminate()
       val terminated = Await.result(wt, 10 seconds)
+      system.whenTerminated.isCompleted should ===(true)
       terminated.actor should ===(system.provider.rootGuardian)
       terminated.addressTerminated should ===(true)
       terminated.existenceConfirmed should ===(true)
       terminated should be theSameInstanceAs Await.result(f, 10 seconds)
-      system.awaitTermination(10 seconds)
-      system.isTerminated should ===(true)
     }
 
     "throw RejectedExecutionException when shutdown" in {
       val system2 = ActorSystem("AwaitTermination", AkkaSpec.testConf)
       Await.ready(system2.terminate(), 10 seconds)
-      system2.awaitTermination(10 seconds)
 
       intercept[RejectedExecutionException] {
         system2.registerOnTermination { println("IF YOU SEE THIS THEN THERE'S A BUG HERE") }
diff --git a/akka-actor-tests/src/test/scala/akka/event/AddressTerminatedTopicBenchSpec.scala b/akka-actor-tests/src/test/scala/akka/event/AddressTerminatedTopicBenchSpec.scala
index 486a43c1a7..4c713af608 100644
--- a/akka-actor-tests/src/test/scala/akka/event/AddressTerminatedTopicBenchSpec.scala
+++ b/akka-actor-tests/src/test/scala/akka/event/AddressTerminatedTopicBenchSpec.scala
@@ -44,7 +44,7 @@ class AddressTerminatedTopicBenchSpec extends AkkaSpec("akka.loglevel=INFO") {
         shutdown(sys, 10.seconds, verifySystemShutdown = true)
         log.info("Stopping {} actors took {} ms", num, (System.nanoTime() - t2).nanos.toMillis)
       } finally {
-        if (!sys.isTerminated) shutdown(sys)
+        shutdown(sys)
       }
     }
 
diff --git a/akka-actor/src/main/scala/akka/actor/ActorPath.scala b/akka-actor/src/main/scala/akka/actor/ActorPath.scala
index 632c6b5f5c..30ee513de2 100644
--- a/akka-actor/src/main/scala/akka/actor/ActorPath.scala
+++ b/akka-actor/src/main/scala/akka/actor/ActorPath.scala
@@ -58,9 +58,6 @@ object ActorPath {
     case _                               ⇒ throw new MalformedURLException("cannot parse as ActorPath: " + s)
   }
 
-  @deprecated("Use `isValidPathElement` instead", since = "2.3.8")
-  val ElementRegex = """(?:[-\w:@&=+,.!~*'_;]|%\p{XDigit}{2})(?:[-\w:@&=+,.!~*'$_;]|%\p{XDigit}{2})*""".r
-
   private final val ValidSymbols = """-_.*$+:@&=,!~';"""
 
   private final val ValidPathCode = -1
diff --git a/akka-actor/src/main/scala/akka/actor/ActorSelection.scala b/akka-actor/src/main/scala/akka/actor/ActorSelection.scala
index 319160be50..0c501dc466 100644
--- a/akka-actor/src/main/scala/akka/actor/ActorSelection.scala
+++ b/akka-actor/src/main/scala/akka/actor/ActorSelection.scala
@@ -3,6 +3,7 @@
  */
 package akka.actor
 
+import scala.language.implicitConversions
 import java.util.concurrent.CompletionStage
 
 import scala.annotation.tailrec
@@ -231,7 +232,7 @@ object ActorSelection {
                     matchingChildren.foreach(_.tell(sel.msg, sender))
                 } else {
                   val matchingChildren = chldr.filter(c ⇒ p.pattern.matcher(c.path.name).matches)
-                  // don't send to emptyRef after wildcard fan-out 
+                  // don't send to emptyRef after wildcard fan-out
                   if (matchingChildren.isEmpty && !sel.wildcardFanOut)
                     emptyRef.tell(sel, sender)
                   else {
diff --git a/akka-actor/src/main/scala/akka/actor/ActorSystem.scala b/akka-actor/src/main/scala/akka/actor/ActorSystem.scala
index 211ab221e6..d46825af38 100644
--- a/akka-actor/src/main/scala/akka/actor/ActorSystem.scala
+++ b/akka-actor/src/main/scala/akka/actor/ActorSystem.scala
@@ -523,42 +523,6 @@ abstract class ActorSystem extends ActorRefFactory {
    */
   def registerOnTermination(code: Runnable): Unit
 
-  /**
-   * Block current thread until the system has been shutdown, or the specified
-   * timeout has elapsed. This will block until after all on termination
-   * callbacks have been run.
-   *
-   * Throws TimeoutException in case of timeout.
-   */
-  @deprecated("Use Await.result(whenTerminated, timeout) instead", "2.4")
-  def awaitTermination(timeout: Duration): Unit
-
-  /**
-   * Block current thread until the system has been shutdown. This will
-   * block until after all on termination callbacks have been run.
-   */
-  @deprecated("Use Await.result(whenTerminated, Duration.Inf) instead", "2.4")
-  def awaitTermination(): Unit
-
-  /**
-   * Stop this actor system. This will stop the guardian actor, which in turn
-   * will recursively stop all its child actors, then the system guardian
-   * (below which the logging actors reside) and the execute all registered
-   * termination handlers (see [[ActorSystem#registerOnTermination]]).
-   */
-  @deprecated("Use the terminate() method instead", "2.4")
-  def shutdown(): Unit
-
-  /**
-   * Query the termination status: if it returns true, all callbacks have run
-   * and the ActorSystem has been fully stopped, i.e.
-   * `awaitTermination(0 seconds)` would return normally. If this method
-   * returns `false`, the status is actually unknown, since it might have
-   * changed since you queried it.
-   */
-  @deprecated("Use the whenTerminated method instead.", "2.4")
-  def isTerminated: Boolean
-
   /**
    * Terminates this actor system. This will stop the guardian actor, which in turn
    * will recursively stop all its child actors, then the system guardian
@@ -820,11 +784,6 @@ private[akka] class ActorSystemImpl(
   def start(): this.type = _start
   def registerOnTermination[T](code: ⇒ T) { registerOnTermination(new Runnable { def run = code }) }
   def registerOnTermination(code: Runnable) { terminationCallbacks.add(code) }
-  override def awaitTermination(timeout: Duration) { Await.ready(whenTerminated, timeout) }
-  override def awaitTermination() = awaitTermination(Duration.Inf)
-  override def isTerminated = whenTerminated.isCompleted
-
-  override def shutdown(): Unit = terminate()
 
   override def terminate(): Future[Terminated] = {
     if (!settings.LogDeadLettersDuringShutdown) logDeadLetterListener foreach stop
diff --git a/akka-actor/src/main/scala/akka/event/EventBus.scala b/akka-actor/src/main/scala/akka/event/EventBus.scala
index b3599cd9d8..e3969b88e4 100644
--- a/akka-actor/src/main/scala/akka/event/EventBus.scala
+++ b/akka-actor/src/main/scala/akka/event/EventBus.scala
@@ -412,112 +412,3 @@ trait ManagedActorClassification { this: ActorEventBus with ActorClassifier ⇒
   }
 }
 
-/**
- * Maps ActorRefs to ActorRefs to form an EventBus where ActorRefs can listen to other ActorRefs
- */
-@deprecated("Use Managed ActorClassification instead", "2.4")
-trait ActorClassification { this: ActorEventBus with ActorClassifier ⇒
-  import java.util.concurrent.ConcurrentHashMap
-  import scala.annotation.tailrec
-  private val empty = immutable.TreeSet.empty[ActorRef]
-  private val mappings = new ConcurrentHashMap[ActorRef, immutable.TreeSet[ActorRef]](mapSize)
-
-  @tailrec
-  protected final def associate(monitored: ActorRef, monitor: ActorRef): Boolean = {
-    val current = mappings get monitored
-    current match {
-      case null ⇒
-        if (monitored.isTerminated) false
-        else {
-          if (mappings.putIfAbsent(monitored, empty + monitor) ne null) associate(monitored, monitor)
-          else if (monitored.isTerminated) !dissociate(monitored, monitor) else true
-        }
-      case raw: immutable.TreeSet[_] ⇒
-        val v = raw.asInstanceOf[immutable.TreeSet[ActorRef]]
-        if (monitored.isTerminated) false
-        if (v.contains(monitor)) true
-        else {
-          val added = v + monitor
-          if (!mappings.replace(monitored, v, added)) associate(monitored, monitor)
-          else if (monitored.isTerminated) !dissociate(monitored, monitor) else true
-        }
-    }
-  }
-
-  protected final def dissociate(monitored: ActorRef): immutable.Iterable[ActorRef] = {
-    @tailrec
-    def dissociateAsMonitored(monitored: ActorRef): immutable.Iterable[ActorRef] = {
-      val current = mappings get monitored
-      current match {
-        case null ⇒ empty
-        case raw: immutable.TreeSet[_] ⇒
-          val v = raw.asInstanceOf[immutable.TreeSet[ActorRef]]
-          if (!mappings.remove(monitored, v)) dissociateAsMonitored(monitored)
-          else v
-      }
-    }
-
-    def dissociateAsMonitor(monitor: ActorRef): Unit = {
-      val i = mappings.entrySet.iterator
-      while (i.hasNext()) {
-        val entry = i.next()
-        val v = entry.getValue
-        v match {
-          case raw: immutable.TreeSet[_] ⇒
-            val monitors = raw.asInstanceOf[immutable.TreeSet[ActorRef]]
-            if (monitors.contains(monitor))
-              dissociate(entry.getKey, monitor)
-          case _ ⇒ //Dun care
-        }
-      }
-    }
-
-    try { dissociateAsMonitored(monitored) } finally { dissociateAsMonitor(monitored) }
-  }
-
-  @tailrec
-  protected final def dissociate(monitored: ActorRef, monitor: ActorRef): Boolean = {
-    val current = mappings get monitored
-    current match {
-      case null ⇒ false
-      case raw: immutable.TreeSet[_] ⇒
-        val v = raw.asInstanceOf[immutable.TreeSet[ActorRef]]
-        val removed = v - monitor
-        if (removed eq raw) false
-        else if (removed.isEmpty) {
-          if (!mappings.remove(monitored, v)) dissociate(monitored, monitor) else true
-        } else {
-          if (!mappings.replace(monitored, v, removed)) dissociate(monitored, monitor) else true
-        }
-    }
-  }
-
-  /**
-   * Returns the Classifier associated with the specified Event
-   */
-  protected def classify(event: Event): Classifier
-
-  /**
-   * This is a size hint for the number of Classifiers you expect to have (use powers of 2)
-   */
-  protected def mapSize: Int
-
-  def publish(event: Event): Unit = mappings.get(classify(event)) match {
-    case null ⇒ ()
-    case some ⇒ some foreach { _ ! event }
-  }
-
-  def subscribe(subscriber: Subscriber, to: Classifier): Boolean =
-    if (subscriber eq null) throw new IllegalArgumentException("Subscriber is null")
-    else if (to eq null) throw new IllegalArgumentException("Classifier is null")
-    else associate(to, subscriber)
-
-  def unsubscribe(subscriber: Subscriber, from: Classifier): Boolean =
-    if (subscriber eq null) throw new IllegalArgumentException("Subscriber is null")
-    else if (from eq null) throw new IllegalArgumentException("Classifier is null")
-    else dissociate(from, subscriber)
-
-  def unsubscribe(subscriber: Subscriber): Unit =
-    if (subscriber eq null) throw new IllegalArgumentException("Subscriber is null")
-    else dissociate(subscriber)
-}
diff --git a/akka-actor/src/main/scala/akka/event/EventStream.scala b/akka-actor/src/main/scala/akka/event/EventStream.scala
index caf4a0d4f4..00ddbe550d 100644
--- a/akka-actor/src/main/scala/akka/event/EventStream.scala
+++ b/akka-actor/src/main/scala/akka/event/EventStream.scala
@@ -11,11 +11,6 @@ import akka.util.Subclassification
 import java.util.concurrent.atomic.AtomicReference
 import scala.annotation.tailrec
 
-object EventStream {
-  @deprecated("Use explicit `system.eventStream` instead", "2.4")
-  implicit def fromActorSystem(system: ActorSystem) = system.eventStream
-}
-
 /**
  * An Akka EventStream is a pub-sub stream of events both system and user generated,
  * where subscribers are ActorRefs and the channels are Classes and Events are any java.lang.Object.
@@ -29,9 +24,6 @@ class EventStream(sys: ActorSystem, private val debug: Boolean) extends LoggingB
 
   def this(sys: ActorSystem) = this(sys, debug = false)
 
-  @deprecated("Use constructor with ActorSystem parameter", "2.4")
-  def this(debug: Boolean = false) = this(sys = null, debug)
-
   type Event = AnyRef
   type Classifier = Class[_]
 
diff --git a/akka-actor/src/main/scala/akka/event/japi/EventBusJavaAPI.scala b/akka-actor/src/main/scala/akka/event/japi/EventBusJavaAPI.scala
index dc715c6439..621172ac09 100644
--- a/akka-actor/src/main/scala/akka/event/japi/EventBusJavaAPI.scala
+++ b/akka-actor/src/main/scala/akka/event/japi/EventBusJavaAPI.scala
@@ -217,35 +217,3 @@ abstract class ManagedActorEventBus[E](system: ActorSystem) extends EventBus[E,
   override def publish(event: E): Unit = bus.publish(event)
 }
 
-/**
- * Java API: See documentation for [[akka.event.ActorClassification]]
- * An EventBus where the Subscribers are ActorRefs and the Classifier is ActorRef
- * Means that ActorRefs "listen" to other ActorRefs
- * E is the Event type
- */
-@deprecated("Use ManagedActorEventBus instead", "2.4")
-abstract class ActorEventBus[E] extends EventBus[E, ActorRef, ActorRef] {
-  private val bus = new akka.event.ActorEventBus with akka.event.ActorClassification with akka.event.ActorClassifier {
-    type Event = E
-
-    override protected def mapSize: Int = ActorEventBus.this.mapSize
-
-    override protected def classify(event: E): ActorRef =
-      ActorEventBus.this.classify(event)
-  }
-
-  /**
-   * This is a size hint for the number of Classifiers you expect to have (use powers of 2)
-   */
-  protected def mapSize(): Int
-
-  /**
-   * Returns the Classifier associated with the given Event
-   */
-  protected def classify(event: E): ActorRef
-
-  override def subscribe(subscriber: ActorRef, to: ActorRef): Boolean = bus.subscribe(subscriber, to)
-  override def unsubscribe(subscriber: ActorRef, from: ActorRef): Boolean = bus.unsubscribe(subscriber, from)
-  override def unsubscribe(subscriber: ActorRef): Unit = bus.unsubscribe(subscriber)
-  override def publish(event: E): Unit = bus.publish(event)
-}
diff --git a/akka-actor/src/main/scala/akka/pattern/AskSupport.scala b/akka-actor/src/main/scala/akka/pattern/AskSupport.scala
index b3772dd43e..b9f33f7527 100644
--- a/akka-actor/src/main/scala/akka/pattern/AskSupport.scala
+++ b/akka-actor/src/main/scala/akka/pattern/AskSupport.scala
@@ -438,9 +438,6 @@ private[akka] final class PromiseActorRef private (val provider: ActorRefProvide
   import AbstractPromiseActorRef.{ stateOffset, watchedByOffset }
   import PromiseActorRef._
 
-  @deprecated("Use the full constructor", "2.4")
-  def this(provider: ActorRefProvider, result: Promise[Any]) = this(provider, result, "unknown")
-
   // This is necessary for weaving the PromiseActorRef into the asked message, i.e. the replyTo pattern.
   @volatile var messageClassName = _mcn
 
@@ -607,7 +604,4 @@ private[akka] object PromiseActorRef {
     a
   }
 
-  @deprecated("Use apply with messageClassName and sender parameters", "2.4")
-  def apply(provider: ActorRefProvider, timeout: Timeout, targetName: String): PromiseActorRef =
-    apply(provider, timeout, targetName, "unknown", Actor.noSender)
 }
diff --git a/akka-actor/src/main/scala/akka/routing/Balancing.scala b/akka-actor/src/main/scala/akka/routing/Balancing.scala
index d252f97c16..0fd0d193dd 100644
--- a/akka-actor/src/main/scala/akka/routing/Balancing.scala
+++ b/akka-actor/src/main/scala/akka/routing/Balancing.scala
@@ -66,7 +66,7 @@ private[akka] final class BalancingRoutingLogic extends RoutingLogic {
  */
 @SerialVersionUID(1L)
 final case class BalancingPool(
-  override val nrOfInstances:      Int,
+  val nrOfInstances:               Int,
   override val supervisorStrategy: SupervisorStrategy = Pool.defaultSupervisorStrategy,
   override val routerDispatcher:   String             = Dispatchers.DefaultDispatcherId)
   extends Pool {
diff --git a/akka-actor/src/main/scala/akka/routing/Broadcast.scala b/akka-actor/src/main/scala/akka/routing/Broadcast.scala
index 0d095a9b00..edacda0b0b 100644
--- a/akka-actor/src/main/scala/akka/routing/Broadcast.scala
+++ b/akka-actor/src/main/scala/akka/routing/Broadcast.scala
@@ -56,7 +56,7 @@ final class BroadcastRoutingLogic extends RoutingLogic {
  */
 @SerialVersionUID(1L)
 final case class BroadcastPool(
-  override val nrOfInstances: Int, override val resizer: Option[Resizer] = None,
+  val nrOfInstances: Int, override val resizer: Option[Resizer] = None,
   override val supervisorStrategy: SupervisorStrategy = Pool.defaultSupervisorStrategy,
   override val routerDispatcher:   String             = Dispatchers.DefaultDispatcherId,
   override val usePoolDispatcher:  Boolean            = false)
@@ -118,7 +118,7 @@ final case class BroadcastPool(
  */
 @SerialVersionUID(1L)
 final case class BroadcastGroup(
-  override val paths:            immutable.Iterable[String],
+  val paths:                     immutable.Iterable[String],
   override val routerDispatcher: String                     = Dispatchers.DefaultDispatcherId)
   extends Group {
 
diff --git a/akka-actor/src/main/scala/akka/routing/ConsistentHashing.scala b/akka-actor/src/main/scala/akka/routing/ConsistentHashing.scala
index cf4cc44830..4a338e337a 100644
--- a/akka-actor/src/main/scala/akka/routing/ConsistentHashing.scala
+++ b/akka-actor/src/main/scala/akka/routing/ConsistentHashing.scala
@@ -267,7 +267,7 @@ final case class ConsistentHashingRoutingLogic(
  */
 @SerialVersionUID(1L)
 final case class ConsistentHashingPool(
-  override val nrOfInstances:      Int,
+  val nrOfInstances:               Int,
   override val resizer:            Option[Resizer]                               = None,
   val virtualNodesFactor:          Int                                           = 0,
   val hashMapping:                 ConsistentHashingRouter.ConsistentHashMapping = ConsistentHashingRouter.emptyConsistentHashMapping,
@@ -355,7 +355,7 @@ final case class ConsistentHashingPool(
  */
 @SerialVersionUID(1L)
 final case class ConsistentHashingGroup(
-  override val paths:            immutable.Iterable[String],
+  val paths:                     immutable.Iterable[String],
   val virtualNodesFactor:        Int                                           = 0,
   val hashMapping:               ConsistentHashingRouter.ConsistentHashMapping = ConsistentHashingRouter.emptyConsistentHashMapping,
   override val routerDispatcher: String                                        = Dispatchers.DefaultDispatcherId)
diff --git a/akka-actor/src/main/scala/akka/routing/Random.scala b/akka-actor/src/main/scala/akka/routing/Random.scala
index de549239db..e650466f20 100644
--- a/akka-actor/src/main/scala/akka/routing/Random.scala
+++ b/akka-actor/src/main/scala/akka/routing/Random.scala
@@ -57,7 +57,7 @@ final class RandomRoutingLogic extends RoutingLogic {
  */
 @SerialVersionUID(1L)
 final case class RandomPool(
-  override val nrOfInstances: Int, override val resizer: Option[Resizer] = None,
+  val nrOfInstances: Int, override val resizer: Option[Resizer] = None,
   override val supervisorStrategy: SupervisorStrategy = Pool.defaultSupervisorStrategy,
   override val routerDispatcher:   String             = Dispatchers.DefaultDispatcherId,
   override val usePoolDispatcher:  Boolean            = false)
@@ -119,7 +119,7 @@ final case class RandomPool(
  */
 @SerialVersionUID(1L)
 final case class RandomGroup(
-  override val paths:            immutable.Iterable[String],
+  val paths:                     immutable.Iterable[String],
   override val routerDispatcher: String                     = Dispatchers.DefaultDispatcherId)
   extends Group {
 
diff --git a/akka-actor/src/main/scala/akka/routing/RoundRobin.scala b/akka-actor/src/main/scala/akka/routing/RoundRobin.scala
index 9a1761a924..e2b072c9b3 100644
--- a/akka-actor/src/main/scala/akka/routing/RoundRobin.scala
+++ b/akka-actor/src/main/scala/akka/routing/RoundRobin.scala
@@ -65,7 +65,7 @@ final class RoundRobinRoutingLogic extends RoutingLogic {
  */
 @SerialVersionUID(1L)
 final case class RoundRobinPool(
-  override val nrOfInstances: Int, override val resizer: Option[Resizer] = None,
+  val nrOfInstances: Int, override val resizer: Option[Resizer] = None,
   override val supervisorStrategy: SupervisorStrategy = Pool.defaultSupervisorStrategy,
   override val routerDispatcher:   String             = Dispatchers.DefaultDispatcherId,
   override val usePoolDispatcher:  Boolean            = false)
@@ -128,7 +128,7 @@ final case class RoundRobinPool(
  */
 @SerialVersionUID(1L)
 final case class RoundRobinGroup(
-  override val paths:            immutable.Iterable[String],
+  val paths:                     immutable.Iterable[String],
   override val routerDispatcher: String                     = Dispatchers.DefaultDispatcherId)
   extends Group {
 
diff --git a/akka-actor/src/main/scala/akka/routing/RoutedActorCell.scala b/akka-actor/src/main/scala/akka/routing/RoutedActorCell.scala
index a789e7f8de..45226e813c 100644
--- a/akka-actor/src/main/scala/akka/routing/RoutedActorCell.scala
+++ b/akka-actor/src/main/scala/akka/routing/RoutedActorCell.scala
@@ -102,17 +102,11 @@ private[akka] class RoutedActorCell(
     _router = routerConfig.createRouter(system)
     routerConfig match {
       case pool: Pool ⇒
-        // must not use pool.nrOfInstances(system) for old (not re-compiled) custom routers
-        // for binary backwards compatibility reasons
-        val deprecatedNrOfInstances = pool.nrOfInstances
-        val nrOfRoutees = if (deprecatedNrOfInstances < 0) pool.nrOfInstances(system) else deprecatedNrOfInstances
+        val nrOfRoutees = pool.nrOfInstances(system)
         if (nrOfRoutees > 0)
           addRoutees(Vector.fill(nrOfRoutees)(pool.newRoutee(routeeProps, this)))
       case group: Group ⇒
-        // must not use group.paths(system) for old (not re-compiled) custom routers
-        // for binary backwards compatibility reasons
-        val deprecatedPaths = group.paths
-        val paths = if (deprecatedPaths == null) group.paths(system) else deprecatedPaths
+        val paths = group.paths(system)
         if (paths.nonEmpty)
           addRoutees(paths.map(p ⇒ group.routeeFor(p, this))(collection.breakOut))
       case _ ⇒
diff --git a/akka-actor/src/main/scala/akka/routing/RouterConfig.scala b/akka-actor/src/main/scala/akka/routing/RouterConfig.scala
index bc66e2c060..4c6795b5ca 100644
--- a/akka-actor/src/main/scala/akka/routing/RouterConfig.scala
+++ b/akka-actor/src/main/scala/akka/routing/RouterConfig.scala
@@ -128,15 +128,6 @@ private[akka] trait PoolOverrideUnsetConfig[T <: Pool] extends Pool {
  * Java API: Base class for custom router [[Group]]
  */
 abstract class GroupBase extends Group {
-  @deprecated("Implement getPaths with ActorSystem parameter instead", "2.4")
-  def getPaths: java.lang.Iterable[String] = null
-
-  @deprecated("Use paths with ActorSystem parameter instead", "2.4")
-  override final def paths: immutable.Iterable[String] = {
-    val tmp = getPaths
-    if (tmp != null) immutableSeq(tmp)
-    else null
-  }
 
   def getPaths(system: ActorSystem): java.lang.Iterable[String]
 
@@ -151,9 +142,6 @@ abstract class GroupBase extends Group {
  */
 trait Group extends RouterConfig {
 
-  @deprecated("Implement paths with ActorSystem parameter instead", "2.4")
-  def paths: immutable.Iterable[String] = null
-
   def paths(system: ActorSystem): immutable.Iterable[String]
 
   /**
@@ -191,9 +179,6 @@ abstract class PoolBase extends Pool
  */
 trait Pool extends RouterConfig {
 
-  @deprecated("Implement nrOfInstances with ActorSystem parameter instead", "2.4")
-  def nrOfInstances: Int = -1
-
   /**
    * Initial number of routee instances
    */
diff --git a/akka-actor/src/main/scala/akka/routing/ScatterGatherFirstCompleted.scala b/akka-actor/src/main/scala/akka/routing/ScatterGatherFirstCompleted.scala
index ce6e9edbdf..c8d0c24f94 100644
--- a/akka-actor/src/main/scala/akka/routing/ScatterGatherFirstCompleted.scala
+++ b/akka-actor/src/main/scala/akka/routing/ScatterGatherFirstCompleted.scala
@@ -96,7 +96,7 @@ private[akka] final case class ScatterGatherFirstCompletedRoutees(
  */
 @SerialVersionUID(1L)
 final case class ScatterGatherFirstCompletedPool(
-  override val nrOfInstances: Int, override val resizer: Option[Resizer] = None,
+  val nrOfInstances: Int, override val resizer: Option[Resizer] = None,
   within:                          FiniteDuration,
   override val supervisorStrategy: SupervisorStrategy = Pool.defaultSupervisorStrategy,
   override val routerDispatcher:   String             = Dispatchers.DefaultDispatcherId,
@@ -165,7 +165,7 @@ final case class ScatterGatherFirstCompletedPool(
  */
 @SerialVersionUID(1L)
 final case class ScatterGatherFirstCompletedGroup(
-  override val paths:            immutable.Iterable[String],
+  val paths:                     immutable.Iterable[String],
   within:                        FiniteDuration,
   override val routerDispatcher: String                     = Dispatchers.DefaultDispatcherId)
   extends Group {
diff --git a/akka-actor/src/main/scala/akka/routing/SmallestMailbox.scala b/akka-actor/src/main/scala/akka/routing/SmallestMailbox.scala
index 99a69b3a8e..48c4e301eb 100644
--- a/akka-actor/src/main/scala/akka/routing/SmallestMailbox.scala
+++ b/akka-actor/src/main/scala/akka/routing/SmallestMailbox.scala
@@ -173,7 +173,7 @@ class SmallestMailboxRoutingLogic extends RoutingLogic {
  */
 @SerialVersionUID(1L)
 final case class SmallestMailboxPool(
-  override val nrOfInstances: Int, override val resizer: Option[Resizer] = None,
+  val nrOfInstances: Int, override val resizer: Option[Resizer] = None,
   override val supervisorStrategy: SupervisorStrategy = Pool.defaultSupervisorStrategy,
   override val routerDispatcher:   String             = Dispatchers.DefaultDispatcherId,
   override val usePoolDispatcher:  Boolean            = false)
diff --git a/akka-actor/src/main/scala/akka/routing/TailChopping.scala b/akka-actor/src/main/scala/akka/routing/TailChopping.scala
index 4279e7a77d..7047f3ee0d 100644
--- a/akka-actor/src/main/scala/akka/routing/TailChopping.scala
+++ b/akka-actor/src/main/scala/akka/routing/TailChopping.scala
@@ -141,7 +141,7 @@ private[akka] final case class TailChoppingRoutees(
  */
 @SerialVersionUID(1L)
 final case class TailChoppingPool(
-  override val nrOfInstances: Int, override val resizer: Option[Resizer] = None,
+  val nrOfInstances: Int, override val resizer: Option[Resizer] = None,
   within:                          FiniteDuration,
   interval:                        FiniteDuration,
   override val supervisorStrategy: SupervisorStrategy = Pool.defaultSupervisorStrategy,
@@ -227,7 +227,7 @@ final case class TailChoppingPool(
  *   router management messages
  */
 final case class TailChoppingGroup(
-  override val paths:            immutable.Iterable[String],
+  val paths:                     immutable.Iterable[String],
   within:                        FiniteDuration,
   interval:                      FiniteDuration,
   override val routerDispatcher: String                     = Dispatchers.DefaultDispatcherId) extends Group {
diff --git a/akka-actor/src/main/scala/akka/serialization/Serializer.scala b/akka-actor/src/main/scala/akka/serialization/Serializer.scala
index 1a4b073cd2..595ca4084b 100644
--- a/akka-actor/src/main/scala/akka/serialization/Serializer.scala
+++ b/akka-actor/src/main/scala/akka/serialization/Serializer.scala
@@ -281,14 +281,6 @@ object JavaSerializer {
  */
 class JavaSerializer(val system: ExtendedActorSystem) extends BaseSerializer {
 
-  @deprecated("Use constructor with ExtendedActorSystem", "2.4")
-  def this() = this(null)
-
-  // TODO remove this when deprecated this() is removed
-  override val identifier: Int =
-    if (system eq null) 1
-    else identifierFromConfig
-
   def includeManifest: Boolean = false
 
   def toBinary(o: AnyRef): Array[Byte] = {
@@ -324,14 +316,6 @@ class NullSerializer extends Serializer {
  */
 class ByteArraySerializer(val system: ExtendedActorSystem) extends BaseSerializer with ByteBufferSerializer {
 
-  @deprecated("Use constructor with ExtendedActorSystem", "2.4")
-  def this() = this(null)
-
-  // TODO remove this when deprecated this() is removed
-  override val identifier: Int =
-    if (system eq null) 4
-    else identifierFromConfig
-
   def includeManifest: Boolean = false
   def toBinary(o: AnyRef): Array[Byte] = o match {
     case null           ⇒ null
diff --git a/akka-actor/src/main/scala/akka/util/Crypt.scala b/akka-actor/src/main/scala/akka/util/Crypt.scala
deleted file mode 100644
index 4f0c0f933e..0000000000
--- a/akka-actor/src/main/scala/akka/util/Crypt.scala
+++ /dev/null
@@ -1,41 +0,0 @@
-/**
- * Copyright (C) 2009-2017 Lightbend Inc. <http://www.lightbend.com>
- */
-
-package akka.util
-
-import java.security.{ MessageDigest, SecureRandom }
-@deprecated(message = "Not in use.", since = "2.4-M1")
-object Crypt {
-  val hex = "0123456789ABCDEF"
-  val lineSeparator = System.getProperty("line.separator")
-
-  lazy val random = SecureRandom.getInstance("SHA1PRNG")
-
-  def md5(text: String): String = md5(unifyLineSeparator(text).getBytes("ASCII"))
-
-  def md5(bytes: Array[Byte]): String = digest(bytes, MessageDigest.getInstance("MD5"))
-
-  def sha1(text: String): String = sha1(unifyLineSeparator(text).getBytes("ASCII"))
-
-  def sha1(bytes: Array[Byte]): String = digest(bytes, MessageDigest.getInstance("SHA1"))
-
-  def generateSecureCookie: String = {
-    val bytes = Array.fill(32)(0.byteValue)
-    random.nextBytes(bytes)
-    sha1(bytes)
-  }
-
-  def digest(bytes: Array[Byte], md: MessageDigest): String = {
-    md.update(bytes)
-    hexify(md.digest)
-  }
-
-  def hexify(bytes: Array[Byte]): String = {
-    val builder = new java.lang.StringBuilder(bytes.length * 2)
-    bytes.foreach { byte ⇒ builder.append(hex.charAt((byte & 0xF0) >> 4)).append(hex.charAt(byte & 0xF)) }
-    builder.toString
-  }
-
-  private def unifyLineSeparator(text: String): String = text.replaceAll(lineSeparator, "\n")
-}
diff --git a/akka-cluster-metrics/src/main/scala/akka/cluster/metrics/ClusterMetricsRouting.scala b/akka-cluster-metrics/src/main/scala/akka/cluster/metrics/ClusterMetricsRouting.scala
index 064cd62f75..7e59948277 100644
--- a/akka-cluster-metrics/src/main/scala/akka/cluster/metrics/ClusterMetricsRouting.scala
+++ b/akka-cluster-metrics/src/main/scala/akka/cluster/metrics/ClusterMetricsRouting.scala
@@ -121,7 +121,7 @@ final case class AdaptiveLoadBalancingRoutingLogic(system: ActorSystem, metricsS
 @SerialVersionUID(1L)
 final case class AdaptiveLoadBalancingPool(
   metricsSelector:                 MetricsSelector    = MixMetricsSelector,
-  override val nrOfInstances:      Int                = 0,
+  val nrOfInstances:               Int                = 0,
   override val supervisorStrategy: SupervisorStrategy = Pool.defaultSupervisorStrategy,
   override val routerDispatcher:   String             = Dispatchers.DefaultDispatcherId,
   override val usePoolDispatcher:  Boolean            = false)
@@ -203,7 +203,7 @@ final case class AdaptiveLoadBalancingPool(
 @SerialVersionUID(1L)
 final case class AdaptiveLoadBalancingGroup(
   metricsSelector:               MetricsSelector            = MixMetricsSelector,
-  override val paths:            immutable.Iterable[String] = Nil,
+  val paths:                     immutable.Iterable[String] = Nil,
   override val routerDispatcher: String                     = Dispatchers.DefaultDispatcherId)
   extends Group {
 
diff --git a/akka-cluster/src/main/scala/akka/cluster/protobuf/ClusterMessageSerializer.scala b/akka-cluster/src/main/scala/akka/cluster/protobuf/ClusterMessageSerializer.scala
index dccab336f0..2fcd7f589a 100644
--- a/akka-cluster/src/main/scala/akka/cluster/protobuf/ClusterMessageSerializer.scala
+++ b/akka-cluster/src/main/scala/akka/cluster/protobuf/ClusterMessageSerializer.scala
@@ -26,14 +26,6 @@ import akka.cluster.InternalClusterAction.ExitingConfirmed
  */
 class ClusterMessageSerializer(val system: ExtendedActorSystem) extends BaseSerializer {
 
-  @deprecated("Use constructor with ExtendedActorSystem", "2.4")
-  def this() = this(null)
-
-  // TODO remove this when deprecated this() is removed
-  override val identifier: Int =
-    if (system eq null) 5
-    else identifierFromConfig
-
   private final val BufferSize = 1024 * 4
   // must be lazy because serializer is initialized from Cluster extension constructor
   private lazy val GossipTimeToLive = Cluster(system).settings.GossipTimeToLive
diff --git a/akka-persistence/src/main/scala/akka/persistence/Eventsourced.scala b/akka-persistence/src/main/scala/akka/persistence/Eventsourced.scala
index f2abba6607..acd231bba7 100644
--- a/akka-persistence/src/main/scala/akka/persistence/Eventsourced.scala
+++ b/akka-persistence/src/main/scala/akka/persistence/Eventsourced.scala
@@ -344,10 +344,6 @@ private[persistence] trait Eventsourced extends Snapshotter with PersistenceStas
     }
   }
 
-  @deprecated("use persistAll instead", "2.4")
-  def persist[A](events: immutable.Seq[A])(handler: A ⇒ Unit): Unit =
-    persistAll(events)(handler)
-
   /**
    * Asynchronously persists `event`. On successful persistence, `handler` is called with the
    * persisted event.
@@ -397,10 +393,6 @@ private[persistence] trait Eventsourced extends Snapshotter with PersistenceStas
     }
   }
 
-  @deprecated("use persistAllAsync instead", "2.4")
-  def persistAsync[A](events: immutable.Seq[A])(handler: A ⇒ Unit): Unit =
-    persistAllAsync(events)(handler)
-
   /**
    * Defer the handler execution until all pending handlers have been executed.
    * Allows to define logic within the actor, which will respect the invocation-order-guarantee
diff --git a/akka-persistence/src/main/scala/akka/persistence/PersistentActor.scala b/akka-persistence/src/main/scala/akka/persistence/PersistentActor.scala
index 43d3485024..4d6a841547 100644
--- a/akka-persistence/src/main/scala/akka/persistence/PersistentActor.scala
+++ b/akka-persistence/src/main/scala/akka/persistence/PersistentActor.scala
@@ -217,10 +217,6 @@ abstract class UntypedPersistentActor extends UntypedActor with Eventsourced wit
   def persistAll[A](events: JIterable[A], handler: Procedure[A]): Unit =
     persistAll(Util.immutableSeq(events))(event ⇒ handler(event))
 
-  @deprecated("use persistAll instead", "2.4")
-  def persist[A](events: JIterable[A], handler: Procedure[A]): Unit =
-    persistAll(events, handler)
-
   /**
    * JAVA API: asynchronously persists `event`. On successful persistence, `handler` is called with the
    * persisted event.
@@ -377,10 +373,6 @@ abstract class AbstractPersistentActor extends AbstractActor with PersistentActo
   def persistAll[A](events: JIterable[A], handler: Procedure[A]): Unit =
     persistAll(Util.immutableSeq(events))(event ⇒ handler(event))
 
-  @deprecated("use persistAll instead", "2.4")
-  def persist[A](events: JIterable[A], handler: Procedure[A]): Unit =
-    persistAll(events, handler)
-
   /**
    * Java API: asynchronously persists `event`. On successful persistence, `handler` is called with the
    * persisted event.
@@ -413,10 +405,6 @@ abstract class AbstractPersistentActor extends AbstractActor with PersistentActo
   def persistAllAsync[A](events: JIterable[A], handler: Procedure[A]): Unit =
     persistAllAsync(Util.immutableSeq(events))(event ⇒ handler(event))
 
-  @deprecated("use persistAllAsync instead", "2.4")
-  def persistAsync[A](events: JIterable[A], handler: Procedure[A]): Unit =
-    persistAllAsync(events, handler)
-
   /**
    * Defer the handler execution until all pending handlers have been executed.
    * Allows to define logic within the actor, which will respect the invocation-order-guarantee
diff --git a/akka-remote/src/main/scala/akka/remote/DeadlineFailureDetector.scala b/akka-remote/src/main/scala/akka/remote/DeadlineFailureDetector.scala
index 2cb80fed48..f7c2fb831f 100644
--- a/akka-remote/src/main/scala/akka/remote/DeadlineFailureDetector.scala
+++ b/akka-remote/src/main/scala/akka/remote/DeadlineFailureDetector.scala
@@ -41,11 +41,6 @@ class DeadlineFailureDetector(
       acceptableHeartbeatPause = config.getMillisDuration("acceptable-heartbeat-pause"),
       heartbeatInterval = config.getMillisDuration("heartbeat-interval"))
 
-  // for backwards compatibility with 2.3.x
-  @deprecated("Use constructor with acceptableHeartbeatPause and heartbeatInterval", "2.4")
-  def this(acceptableHeartbeatPause: FiniteDuration)(implicit clock: Clock) =
-    this(acceptableHeartbeatPause, heartbeatInterval = 1.millis)(clock)
-
   require(acceptableHeartbeatPause >= Duration.Zero, "failure-detector.acceptable-heartbeat-pause must be >= 0 s")
   require(heartbeatInterval > Duration.Zero, "failure-detector.heartbeat-interval must be > 0 s")
 
diff --git a/akka-remote/src/main/scala/akka/remote/RemotingLifecycleEvent.scala b/akka-remote/src/main/scala/akka/remote/RemotingLifecycleEvent.scala
index de925ca4e0..113e15ce04 100644
--- a/akka-remote/src/main/scala/akka/remote/RemotingLifecycleEvent.scala
+++ b/akka-remote/src/main/scala/akka/remote/RemotingLifecycleEvent.scala
@@ -84,7 +84,7 @@ final case class RemotingErrorEvent(cause: Throwable) extends RemotingLifecycleE
 // For binary compatibility
 object QuarantinedEvent extends AbstractFunction2[Address, Int, QuarantinedEvent] {
 
-  @deprecated("Use long uid apply")
+  @deprecated("Use long uid apply", "2.4.x")
   def apply(address: Address, uid: Int) = new QuarantinedEvent(address, uid)
 }
 
@@ -99,13 +99,13 @@ final case class QuarantinedEvent(address: Address, longUid: Long) extends Remot
 
   // For binary compatibility
 
-  @deprecated("Use long uid constructor")
+  @deprecated("Use long uid constructor", "2.4.x")
   def this(address: Address, uid: Int) = this(address, uid.toLong)
 
-  @deprecated("Use long uid")
+  @deprecated("Use long uid", "2.4.x")
   def uid: Int = longUid.toInt
 
-  @deprecated("Use long uid copy method")
+  @deprecated("Use long uid copy method", "2.4.x")
   def copy(address: Address = address, uid: Int = uid) = new QuarantinedEvent(address, uid)
 }
 
diff --git a/akka-remote/src/main/scala/akka/remote/serialization/MessageContainerSerializer.scala b/akka-remote/src/main/scala/akka/remote/serialization/MessageContainerSerializer.scala
index 1d0e01c3b1..f21906cdc5 100644
--- a/akka-remote/src/main/scala/akka/remote/serialization/MessageContainerSerializer.scala
+++ b/akka-remote/src/main/scala/akka/remote/serialization/MessageContainerSerializer.scala
@@ -18,16 +18,8 @@ import akka.serialization.SerializerWithStringManifest
 
 class MessageContainerSerializer(val system: ExtendedActorSystem) extends BaseSerializer {
 
-  @deprecated("Use constructor with ExtendedActorSystem", "2.4")
-  def this() = this(null)
-
   private lazy val serialization = SerializationExtension(system)
 
-  // TODO remove this when deprecated this() is removed
-  override val identifier: Int =
-    if (system eq null) 6
-    else identifierFromConfig
-
   def includeManifest: Boolean = false
 
   def toBinary(obj: AnyRef): Array[Byte] = obj match {
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 63e542e3f0..ac8e758383 100644
--- a/akka-remote/src/main/scala/akka/remote/serialization/ProtobufSerializer.scala
+++ b/akka-remote/src/main/scala/akka/remote/serialization/ProtobufSerializer.scala
@@ -40,17 +40,6 @@ object ProtobufSerializer {
  */
 class ProtobufSerializer(val system: ExtendedActorSystem) extends BaseSerializer {
 
-  @deprecated("Use constructor with ExtendedActorSystem", "2.4")
-  def this() = this(null)
-
-  // TODO remove this when deprecated this() is removed
-  override val identifier: Int =
-    if (system eq null) 2
-    else identifierFromConfig
-
-  @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/akka-stream-tests-tck/src/test/scala/akka/stream/tck/ActorSystemLifecycle.scala b/akka-stream-tests-tck/src/test/scala/akka/stream/tck/ActorSystemLifecycle.scala
index c97bbcb056..bd55d72a15 100644
--- a/akka-stream-tests-tck/src/test/scala/akka/stream/tck/ActorSystemLifecycle.scala
+++ b/akka-stream-tests-tck/src/test/scala/akka/stream/tck/ActorSystemLifecycle.scala
@@ -13,6 +13,7 @@ import akka.event.Logging
 import akka.testkit.TestEvent
 import akka.testkit.EventFilter
 import org.testng.annotations.BeforeClass
+import scala.concurrent.Await
 
 trait ActorSystemLifecycle {
 
@@ -31,8 +32,7 @@ trait ActorSystemLifecycle {
   @AfterClass
   def shutdownActorSystem(): Unit = {
     try {
-      system.terminate()
-      system.awaitTermination(shutdownTimeout)
+      Await.ready(system.terminate(), shutdownTimeout)
     } catch {
       case _: TimeoutException ⇒
         val msg = "Failed to stop [%s] within [%s] \n%s".format(system.name, shutdownTimeout,
diff --git a/akka-stream-tests/src/test/scala/akka/stream/io/TcpSpec.scala b/akka-stream-tests/src/test/scala/akka/stream/io/TcpSpec.scala
index dc84fb9824..3b71b08840 100644
--- a/akka-stream-tests/src/test/scala/akka/stream/io/TcpSpec.scala
+++ b/akka-stream-tests/src/test/scala/akka/stream/io/TcpSpec.scala
@@ -413,7 +413,9 @@ class TcpSpec extends StreamSpec("akka.stream.materializer.subscription-timeout.
 
       result.failed.futureValue shouldBe a[StreamTcpException]
 
-      binding.map(_.unbind()).recover { case NonFatal(_) ⇒ () } foreach (_ ⇒ system2.shutdown())
+      binding.map(_.unbind()).recover { case NonFatal(_) ⇒ () }.foreach { _ ⇒
+        shutdown(system2)
+      }
     }
 
   }
diff --git a/project/MiMa.scala b/project/MiMa.scala
index d48611701f..a421e15ff5 100644
--- a/project/MiMa.scala
+++ b/project/MiMa.scala
@@ -258,6 +258,80 @@ object MiMa extends AutoPlugin {
       // object akka.stream.stage.StatefulStage#Finish does not have a correspondent in current version
       ProblemFilters.exclude[MissingClassProblem]("akka.stream.stage.StatefulStage$Finish$"),
 
+      // #21423 remove deprecated ActorSystem termination methods (in 2.5.x)
+      ProblemFilters.exclude[DirectMissingMethodProblem]("akka.actor.ActorSystemImpl.shutdown"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("akka.actor.ActorSystemImpl.isTerminated"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("akka.actor.ActorSystemImpl.awaitTermination"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("akka.actor.ActorSystemImpl.awaitTermination"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("akka.actor.ActorSystem.shutdown"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("akka.actor.ActorSystem.isTerminated"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("akka.actor.ActorSystem.awaitTermination"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("akka.actor.ActorSystem.awaitTermination"),
+      
+      // #21423 remove deprecated ActorPath.ElementRegex
+      ProblemFilters.exclude[DirectMissingMethodProblem]("akka.actor.ActorPath.ElementRegex"),
+      
+      // #21423 remove some deprecated event bus classes
+      ProblemFilters.exclude[MissingClassProblem]("akka.event.ActorClassification"),
+      ProblemFilters.exclude[MissingClassProblem]("akka.event.EventStream$"),
+      ProblemFilters.exclude[IncompatibleMethTypeProblem]("akka.event.EventStream.this"),
+      ProblemFilters.exclude[MissingClassProblem]("akka.event.japi.ActorEventBus"),
+      
+      // #21423 remove deprecated util.Crypt
+      ProblemFilters.exclude[MissingClassProblem]("akka.util.Crypt"),
+      ProblemFilters.exclude[MissingClassProblem]("akka.util.Crypt$"),
+      
+      // #21423 removal of deprecated serializer constructors (in 2.5.x)
+      ProblemFilters.exclude[DirectMissingMethodProblem]("akka.remote.serialization.ProtobufSerializer.this"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("akka.remote.serialization.MessageContainerSerializer.this"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("akka.remote.serialization.DaemonMsgCreateSerializer.this"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("akka.serialization.JavaSerializer.this"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("akka.serialization.ByteArraySerializer.this"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("akka.cluster.protobuf.ClusterMessageSerializer.this"),
+      
+      // #21423 removal of deprecated constructor in PromiseActorRef
+      ProblemFilters.exclude[DirectMissingMethodProblem]("akka.pattern.PromiseActorRef.this"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("akka.pattern.PromiseActorRef.apply"),
+      
+      // #21423 remove deprecated methods in routing
+      ProblemFilters.exclude[DirectMissingMethodProblem]("akka.routing.Pool.nrOfInstances"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("akka.routing.Group.paths"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("akka.routing.PoolBase.nrOfInstances"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("akka.routing.GroupBase.paths"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("akka.routing.GroupBase.getPaths"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("akka.routing.FromConfig.nrOfInstances"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("akka.remote.routing.RemoteRouterConfig.nrOfInstances"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("akka.cluster.routing.ClusterRouterGroup.paths"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("akka.cluster.routing.ClusterRouterPool.nrOfInstances"),
+      
+      // #21423 remove deprecated persist method (persistAll)
+      // This might filter changes to the ordinary persist method also, but not much to do about that
+      ProblemFilters.exclude[IncompatibleMethTypeProblem]("akka.persistence.UntypedPersistentActor.persist"),
+      ProblemFilters.exclude[IncompatibleMethTypeProblem]("akka.persistence.UntypedPersistentActor.persist"),
+      ProblemFilters.exclude[IncompatibleMethTypeProblem]("akka.persistence.UntypedPersistentActor.persistAsync"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("akka.persistence.Eventsourced.persist"),
+      ProblemFilters.exclude[DirectMissingMethodProblem]("akka.persistence.Eventsourced.persistAsync"),
+      ProblemFilters.exclude[IncompatibleMethTypeProblem]("akka.persistence.AbstractPersistentActor.persist"),
+      ProblemFilters.exclude[IncompatibleMethTypeProblem]("akka.persistence.AbstractPersistentActor.persist"),
+      ProblemFilters.exclude[IncompatibleMethTypeProblem]("akka.persistence.AbstractPersistentActor.persistAsync"),
+      ProblemFilters.exclude[IncompatibleMethTypeProblem]("akka.persistence.AbstractPersistentActor.persistAsync"),
+      ProblemFilters.exclude[IncompatibleMethTypeProblem]("akka.persistence.fsm.AbstractPersistentFSM.persist"),
+      ProblemFilters.exclude[IncompatibleMethTypeProblem]("akka.persistence.fsm.AbstractPersistentFSM.persistAsync"),
+      ProblemFilters.exclude[IncompatibleMethTypeProblem]("akka.persistence.fsm.AbstractPersistentLoggingFSM.persist"),
+      ProblemFilters.exclude[IncompatibleMethTypeProblem]("akka.persistence.fsm.AbstractPersistentLoggingFSM.persistAsync"),
+      ProblemFilters.exclude[IncompatibleMethTypeProblem]("akka.cluster.sharding.PersistentShard.persist"),
+      ProblemFilters.exclude[IncompatibleMethTypeProblem]("akka.cluster.sharding.PersistentShard.persistAsync"),
+      ProblemFilters.exclude[IncompatibleMethTypeProblem]("akka.cluster.sharding.PersistentShardCoordinator.persist"),
+      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 remove deprecated constructor in DeadlineFailureDetector
+      ProblemFilters.exclude[IncompatibleMethTypeProblem]("akka.remote.DeadlineFailureDetector.this"),
+          
       // #21423 removal of deprecated `PersistentView` (in 2.5.x)
       ProblemFilters.exclude[MissingClassProblem]("akka.persistence.Update"),
       ProblemFilters.exclude[MissingClassProblem]("akka.persistence.Update$"),