diff --git a/akka-actor/src/main/resources/reference.conf b/akka-actor/src/main/resources/reference.conf
index 1b167aa9d2..612df3b927 100644
--- a/akka-actor/src/main/resources/reference.conf
+++ b/akka-actor/src/main/resources/reference.conf
@@ -652,7 +652,7 @@ akka {
     # `akka.actor.serialization-identifiers."FQCN" = ID`
     # where `FQCN` is fully qualified class name of the serializer implementation
     # and `ID` is globally unique serializer identifier number.
-    # Identifier values from 0 to 16 are reserved for Akka internal usage.
+    # Identifier values from 0 to 40 are reserved for Akka internal usage.
     serialization-identifiers {
       "akka.serialization.JavaSerializer" = 1
       "akka.serialization.ByteArraySerializer" = 4
diff --git a/akka-actor/src/main/scala/akka/actor/dungeon/Dispatch.scala b/akka-actor/src/main/scala/akka/actor/dungeon/Dispatch.scala
index 873577f3b5..bf3cfcae97 100644
--- a/akka-actor/src/main/scala/akka/actor/dungeon/Dispatch.scala
+++ b/akka-actor/src/main/scala/akka/actor/dungeon/Dispatch.scala
@@ -5,13 +5,14 @@
 package akka.actor.dungeon
 
 import scala.annotation.tailrec
-import akka.dispatch.{ Mailbox, Envelope }
+import akka.dispatch.{ Envelope, Mailbox }
 import akka.dispatch.sysmsg._
 import akka.event.Logging.Error
 import akka.util.Unsafe
 import akka.actor._
 import akka.serialization.SerializationExtension
-import scala.util.control.NonFatal
+
+import scala.util.control.{ NoStackTrace, NonFatal }
 import scala.util.control.Exception.Catcher
 import akka.dispatch.MailboxType
 import akka.dispatch.ProducesMessageQueue
@@ -106,7 +107,11 @@ private[akka] trait Dispatch { this: ActorCell ⇒
       system.eventStream.publish(Error(e, self.path.toString, clazz(actor), "interrupted during message send"))
       Thread.currentThread.interrupt()
     case NonFatal(e) ⇒
-      system.eventStream.publish(Error(e, self.path.toString, clazz(actor), "swallowing exception during message send"))
+      val message = e match {
+        case n: NoStackTrace ⇒ "swallowing exception during message send: " + n.getMessage
+        case _               ⇒ "swallowing exception during message send" // stack trace includes message
+      }
+      system.eventStream.publish(Error(e, self.path.toString, clazz(actor), message))
   }
 
   // ➡➡➡ NEVER SEND THE SAME SYSTEM MESSAGE OBJECT TO TWO ACTORS ⬅⬅⬅
diff --git a/akka-actor/src/main/scala/akka/serialization/Serializer.scala b/akka-actor/src/main/scala/akka/serialization/Serializer.scala
index 928d25a5b4..5032ec9c29 100644
--- a/akka-actor/src/main/scala/akka/serialization/Serializer.scala
+++ b/akka-actor/src/main/scala/akka/serialization/Serializer.scala
@@ -39,7 +39,7 @@ trait Serializer {
 
   /**
    * Completely unique value to identify this implementation of Serializer, used to optimize network traffic.
-   * Values from 0 to 16 are reserved for Akka internal usage.
+   * Values from 0 to 40 are reserved for Akka internal usage.
    */
   def identifier: Int
 
@@ -105,7 +105,7 @@ abstract class SerializerWithStringManifest extends Serializer {
 
   /**
    * Completely unique value to identify this implementation of Serializer, used to optimize network traffic.
-   * Values from 0 to 16 are reserved for Akka internal usage.
+   * Values from 0 to 40 are reserved for Akka internal usage.
    */
   def identifier: Int
 
diff --git a/akka-bench-jmh/src/main/scala/akka/stream/EmptySourceBenchmark.scala b/akka-bench-jmh/src/main/scala/akka/stream/EmptySourceBenchmark.scala
new file mode 100644
index 0000000000..d149a56ec0
--- /dev/null
+++ b/akka-bench-jmh/src/main/scala/akka/stream/EmptySourceBenchmark.scala
@@ -0,0 +1,47 @@
+/**
+ * Copyright (C) 2014-2017 Lightbend Inc. <http://www.lightbend.com>
+ */
+
+package akka.stream
+
+import java.util.concurrent.TimeUnit
+
+import akka.actor.ActorSystem
+import akka.stream.scaladsl._
+import akka.{ Done, NotUsed }
+import org.openjdk.jmh.annotations._
+
+import scala.concurrent._
+import scala.concurrent.duration._
+
+@State(Scope.Benchmark)
+@OutputTimeUnit(TimeUnit.MILLISECONDS)
+@BenchmarkMode(Array(Mode.Throughput))
+class EmptySourceBenchmark {
+  implicit val system = ActorSystem("EmptySourceBenchmark")
+  val materializerSettings = ActorMaterializerSettings(system).withDispatcher("akka.test.stream-dispatcher")
+  implicit val materializer = ActorMaterializer(materializerSettings)
+
+
+  @TearDown
+  def shutdown(): Unit = {
+    Await.result(system.terminate(), 5.seconds)
+  }
+
+  val setup = Source.empty[String].toMat(Sink.ignore)(Keep.right)
+  
+  @Benchmark def empty(): Unit = 
+    Await.result(setup.run(), Duration.Inf)
+
+  
+  /*
+    (not serious benchmark, just sanity check: run on macbook 15, late 2013)
+  
+    While it was a PublisherSource:
+     [info] EmptySourceBenchmark.empty  thrpt   10  11.219 ± 6.498  ops/ms
+     
+    Rewrite to GraphStage:
+     [info] EmptySourceBenchmark.empty  thrpt   10  17.556 ± 2.865  ops/ms
+     
+   */
+}
diff --git a/akka-docs/rst/dev/documentation.rst b/akka-docs/rst/dev/documentation.rst
index 936da82f96..e493d92ef3 100644
--- a/akka-docs/rst/dev/documentation.rst
+++ b/akka-docs/rst/dev/documentation.rst
@@ -144,3 +144,72 @@ If you get the error "unknown locale: UTF-8" when generating the documentation t
   export LANG=en_US.UTF-8
   export LC_ALL=en_US.UTF-8
 
+Installing Sphinx on Linux
+--------------------------
+Install Python with your package manager:
+
+::
+
+  apt-get install python # for Debian based systems
+  yum install python     # for CentOS/RHEL systems
+
+This will automatically add Python executable to your $PATH and pip is a part of the default Python installation. Remember you need `sudo` rights to run this command.
+
+More information in case of trouble:
+https://packaging.python.org/install_requirements_linux/ 
+
+Install Sphinx:
+
+::
+
+  apt-get install python-sphinx # for Debian based systems
+  #alternatively
+  pip install sphinx
+
+For other Linux systems please check Sphinx website:
+http://www.sphinx-doc.org/en/stable/install.html#other-linux-distributions
+
+Install TextLive:
+
+::
+
+  apt-get install texlive-latex-base texlive-latex-extra texlive-latex-recommended
+  # additionally you may need xzdec
+  apt-get install xzdec
+  
+In case you get the following error:
+
+
+
+ Unknown directive ...containerchecksum c59200574a316416a23695c258edf3a32531fbda43ccdc09360ee105c3f07f9fb77df17c4ba4c2ea4f3a5ea6667e064b51e3d8c2fe6c984ba3e71b4e32716955... , please fix it! at /usr/share/texlive/tlpkg/TeXLive/TLPOBJ.pm line 210, <$retfh> line 5579.
+
+you need to specify you want to continue using the 2015 version:
+
+::
+
+  tlmgr option repository ftp://tug.org/historic/systems/texlive/2015/tlnet-final 
+
+Add missing tex packages:
+
+::
+
+  sudo tlmgr update --self
+  sudo tlmgr install titlesec
+  sudo tlmgr install framed
+  sudo tlmgr install threeparttable
+  sudo tlmgr install wrapfig
+  sudo tlmgr install helvetic
+  sudo tlmgr install courier
+  sudo tlmgr install multirow
+  sudo tlmgr install capt-of
+  sudo tlmgr install needspace
+  sudo tlmgr install eqparbox
+  sudo tlmgr install environ
+  sudo tlmgr install trimspaces
+
+If you get the error "unknown locale: UTF-8" when generating the documentation the solution is to define the following environment variables:
+
+::
+
+  export LANG=en_US.UTF-8
+  export LC_ALL=en_US.UTF-8
diff --git a/akka-docs/rst/java/cluster-usage.rst b/akka-docs/rst/java/cluster-usage.rst
index f7ef257843..7f942c2412 100644
--- a/akka-docs/rst/java/cluster-usage.rst
+++ b/akka-docs/rst/java/cluster-usage.rst
@@ -125,7 +125,7 @@ seed nodes in the existing cluster.
 
 If you don't configure seed nodes you need to join the cluster programmatically or manually.
 
-Manual joining can be performed by using ref:`cluster_jmx_java` or :ref:`cluster_http_java`.
+Manual joining can be performed by using :ref:`cluster_jmx_java` or :ref:`cluster_http_java`.
 Joining programmatically can be performed with ``Cluster.get(system).join``. Unsuccessful join attempts are
 automatically retried after the time period defined in configuration property ``retry-unsuccessful-join-after``.
 Retries can be disabled by setting the property to ``off``.
@@ -173,9 +173,9 @@ can be performed automatically or manually. By default it must be done manually,
 It can also be performed programmatically with ``Cluster.get(system).down(address)``.
 
 A pre-packaged solution for the downing problem is provided by
-`Split Brain Resolver <http://doc.akka.io/docs/akka/akka-commercial-addons-1.0/java/split-brain-resolver.html>`_,
+`Split Brain Resolver <http://developer.lightbend.com/docs/akka-commercial-addons/current/split-brain-resolver.html>`_,
 which is part of the `Lightbend Reactive Platform <http://www.lightbend.com/platform>`_.
-If you don’t use RP, you should anyway carefully read the `documentation <http://doc.akka.io/docs/akka/akka-commercial-addons-1.0/java/split-brain-resolver.html>`_
+If you don’t use RP, you should anyway carefully read the `documentation <http://developer.lightbend.com/docs/akka-commercial-addons/current/split-brain-resolver.html>`_
 of the Split Brain Resolver and make sure that the solution you are using handles the concerns
 described there.
 
diff --git a/akka-docs/rst/java/code/docs/remoting/RemoteDeploymentDocTest.java b/akka-docs/rst/java/code/docs/remoting/RemoteDeploymentDocTest.java
index d6b0ac7c20..fc136366ee 100644
--- a/akka-docs/rst/java/code/docs/remoting/RemoteDeploymentDocTest.java
+++ b/akka-docs/rst/java/code/docs/remoting/RemoteDeploymentDocTest.java
@@ -4,6 +4,7 @@
 package docs.remoting;
 
 import akka.testkit.AkkaJUnitActorSystemResource;
+import docs.AbstractJavaTest;
 import org.junit.ClassRule;
 import org.junit.Test;
 
@@ -21,7 +22,7 @@ import akka.remote.RemoteScope;
 
 import akka.actor.AbstractActor;
 
-public class RemoteDeploymentDocTest {
+public class RemoteDeploymentDocTest extends AbstractJavaTest {
 
   public static class SampleActor extends AbstractActor {
     @Override
diff --git a/akka-docs/rst/java/code/docs/serialization/SerializationDocTest.java b/akka-docs/rst/java/code/docs/serialization/SerializationDocTest.java
index f60c87c320..46e07d4197 100644
--- a/akka-docs/rst/java/code/docs/serialization/SerializationDocTest.java
+++ b/akka-docs/rst/java/code/docs/serialization/SerializationDocTest.java
@@ -29,7 +29,7 @@ public class SerializationDocTest {
 
     // Pick a unique identifier for your Serializer,
     // you've got a couple of billions to choose from,
-    // 0 - 16 is reserved by Akka itself
+    // 0 - 40 is reserved by Akka itself
     @Override public int identifier() {
       return 1234567;
     }
@@ -80,7 +80,7 @@ public class SerializationDocTest {
     
     // Pick a unique identifier for your Serializer,
     // you've got a couple of billions to choose from,
-    // 0 - 16 is reserved by Akka itself
+    // 0 - 40 is reserved by Akka itself
     @Override public int identifier() {
       return 1234567;
     }
diff --git a/akka-docs/rst/java/code/docs/stream/QuickStartDocTest.java b/akka-docs/rst/java/code/docs/stream/QuickStartDocTest.java
index 6e41c5557e..e58a55318c 100644
--- a/akka-docs/rst/java/code/docs/stream/QuickStartDocTest.java
+++ b/akka-docs/rst/java/code/docs/stream/QuickStartDocTest.java
@@ -20,6 +20,7 @@ import java.util.concurrent.CompletionStage;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.TimeUnit;
 
+import docs.AbstractJavaTest;
 import scala.concurrent.duration.Duration;
 //#other-imports
 
@@ -29,7 +30,7 @@ import org.junit.*;
  * This class is not meant to be run as a test in the test suite, but it
  * is set up such that it can be run interactively from within an IDE.
  */
-public class QuickStartDocTest {
+public class QuickStartDocTest extends AbstractJavaTest {
   
   static
   //#create-materializer
diff --git a/akka-docs/rst/java/code/docs/testkit/ParentChildTest.java b/akka-docs/rst/java/code/docs/testkit/ParentChildTest.java
index 7c775f4be1..d48034863d 100644
--- a/akka-docs/rst/java/code/docs/testkit/ParentChildTest.java
+++ b/akka-docs/rst/java/code/docs/testkit/ParentChildTest.java
@@ -14,10 +14,11 @@ import akka.testkit.TestProbe;
 
 import com.typesafe.config.ConfigFactory;
 
+import docs.AbstractJavaTest;
 import org.junit.ClassRule;
 import org.junit.Test;
 
-public class ParentChildTest {
+public class ParentChildTest extends AbstractJavaTest {
   @ClassRule
   public static AkkaJUnitActorSystemResource actorSystemResource =
     new AkkaJUnitActorSystemResource("TestKitDocTest",
diff --git a/akka-docs/rst/java/code/docs/testkit/TestKitDocTest.java b/akka-docs/rst/java/code/docs/testkit/TestKitDocTest.java
index 472cf33068..3e9107daf6 100644
--- a/akka-docs/rst/java/code/docs/testkit/TestKitDocTest.java
+++ b/akka-docs/rst/java/code/docs/testkit/TestKitDocTest.java
@@ -6,6 +6,8 @@ package docs.testkit;
 import static org.junit.Assert.*;
 
 import akka.testkit.*;
+import docs.AbstractJavaTest;
+import org.junit.Assert;
 import org.junit.ClassRule;
 import org.junit.Test;
 
@@ -24,7 +26,7 @@ import scala.concurrent.Future;
 import akka.testkit.TestActor.AutoPilot;
 import scala.concurrent.duration.Duration;
 
-public class TestKitDocTest {
+public class TestKitDocTest extends AbstractJavaTest {
 
   @ClassRule
   public static AkkaJUnitActorSystemResource actorSystemResource =
@@ -76,7 +78,7 @@ public class TestKitDocTest {
     final TestActorRef<MyActor> ref = TestActorRef.create(system, props, "myActor");
     try {
       ref.receive(new Exception("expected"));
-      fail("expected an exception to be thrown");
+      Assert.fail("expected an exception to be thrown");
     } catch (Exception e) {
       assertEquals("expected", e.getMessage());
     }
diff --git a/akka-docs/rst/java/code/docs/testkit/TestKitSampleTest.java b/akka-docs/rst/java/code/docs/testkit/TestKitSampleTest.java
index a99ec38c6a..d2706e1b26 100644
--- a/akka-docs/rst/java/code/docs/testkit/TestKitSampleTest.java
+++ b/akka-docs/rst/java/code/docs/testkit/TestKitSampleTest.java
@@ -4,6 +4,7 @@
 package docs.testkit;
 
 //#fullsample
+import docs.AbstractJavaTest;
 import org.junit.AfterClass;
 import org.junit.Assert;
 import org.junit.BeforeClass;
@@ -16,7 +17,7 @@ import akka.actor.AbstractActor;
 import akka.testkit.JavaTestKit;
 import scala.concurrent.duration.Duration;
 
-public class TestKitSampleTest {
+public class TestKitSampleTest extends AbstractJavaTest {
   
   public static class SomeActor extends AbstractActor {
     ActorRef target = null;
diff --git a/akka-docs/rst/java/persistence.rst b/akka-docs/rst/java/persistence.rst
index b19b241d19..3618ccb16c 100644
--- a/akka-docs/rst/java/persistence.rst
+++ b/akka-docs/rst/java/persistence.rst
@@ -219,10 +219,10 @@ maximum stash capacity in the mailbox configuration::
 
 Note that the stash capacity is per actor. If you have many persistent actors, e.g. when using cluster sharding,
 you may need to define a small stash capacity to ensure that the total number of stashed messages in the system
-don't consume too much memory. Additionally, The persistent actor defines three strategies to handle failure when the 
+doesn't consume too much memory. Additionally, the persistent actor defines three strategies to handle failure when the 
 internal stash capacity is exceeded. The default overflow strategy is the ``ThrowOverflowExceptionStrategy``, which 
-discards the current received message and throws a ``StashOverflowException``, causing actor restart if default 
-supervision strategy is used. you can override the ``internalStashOverflowStrategy`` method to return 
+discards the current received message and throws a ``StashOverflowException``, causing actor restart if the default 
+supervision strategy is used. You can override the ``internalStashOverflowStrategy`` method to return 
 ``DiscardToDeadLetterStrategy`` or ``ReplyToStrategy`` for any "individual" persistent actor, or define the "default" 
 for all persistent actors by providing FQCN, which must be a subclass of ``StashOverflowStrategyConfigurator``, in the 
 persistence configuration::
@@ -233,7 +233,7 @@ persistence configuration::
 The ``DiscardToDeadLetterStrategy`` strategy also has a pre-packaged companion configurator 
 ``akka.persistence.DiscardConfigurator``.
 
-You can also query default strategy via the Akka persistence extension singleton::
+You can also query the default strategy via the Akka persistence extension singleton::
 
     Persistence.get(getContext().system()).defaultInternalStashOverflowStrategy();
 
diff --git a/akka-docs/rst/scala/cluster-usage.rst b/akka-docs/rst/scala/cluster-usage.rst
index 93131361c5..bc3fd378d8 100644
--- a/akka-docs/rst/scala/cluster-usage.rst
+++ b/akka-docs/rst/scala/cluster-usage.rst
@@ -119,7 +119,7 @@ seed nodes in the existing cluster.
 
 If you don't configure seed nodes you need to join the cluster programmatically or manually.
 
-Manual joining can be performed by using ref:`cluster_jmx_scala` or :ref:`cluster_http_scala`.
+Manual joining can be performed by using :ref:`cluster_jmx_scala` or :ref:`cluster_http_scala`.
 Joining programmatically can be performed with ``Cluster(system).join``. Unsuccessful join attempts are
 automatically retried after the time period defined in configuration property ``retry-unsuccessful-join-after``.
 Retries can be disabled by setting the property to ``off``.
@@ -168,9 +168,9 @@ can be performed automatically or manually. By default it must be done manually,
 It can also be performed programmatically with ``Cluster(system).down(address)``.
 
 A pre-packaged solution for the downing problem is provided by
-`Split Brain Resolver <http://doc.akka.io/docs/akka/akka-commercial-addons-1.0/scala/split-brain-resolver.html>`_,
+`Split Brain Resolver <http://developer.lightbend.com/docs/akka-commercial-addons/current/split-brain-resolver.html>`_,
 which is part of the `Lightbend Reactive Platform <http://www.lightbend.com/platform>`_. 
-If you don’t use RP, you should anyway carefully read the `documentation <http://doc.akka.io/docs/akka/akka-commercial-addons-1.0/scala/split-brain-resolver.html>`_
+If you don’t use RP, you should anyway carefully read the `documentation <http://developer.lightbend.com/docs/akka-commercial-addons/current/split-brain-resolver.html>`_
 of the Split Brain Resolver and make sure that the solution you are using handles the concerns
 described there.
 
diff --git a/akka-docs/rst/scala/code/docs/serialization/SerializationDocSpec.scala b/akka-docs/rst/scala/code/docs/serialization/SerializationDocSpec.scala
index 369e51c48c..85787c4eec 100644
--- a/akka-docs/rst/scala/code/docs/serialization/SerializationDocSpec.scala
+++ b/akka-docs/rst/scala/code/docs/serialization/SerializationDocSpec.scala
@@ -25,7 +25,7 @@ package docs.serialization {
 
     // Pick a unique identifier for your Serializer,
     // you've got a couple of billions to choose from,
-    // 0 - 16 is reserved by Akka itself
+    // 0 - 40 is reserved by Akka itself
     def identifier = 1234567
 
     // "toBinary" serializes the given object to an Array of Bytes
@@ -58,7 +58,7 @@ package docs.serialization {
 
     // Pick a unique identifier for your Serializer,
     // you've got a couple of billions to choose from,
-    // 0 - 16 is reserved by Akka itself
+    // 0 - 40 is reserved by Akka itself
     def identifier = 1234567
 
     // The manifest (type hint) that will be provided in the fromBinary method
diff --git a/akka-docs/rst/scala/code/docs/stream/TwitterStreamQuickstartDocSpec.scala b/akka-docs/rst/scala/code/docs/stream/TwitterStreamQuickstartDocSpec.scala
index 4b346d28c4..e8628b9d84 100644
--- a/akka-docs/rst/scala/code/docs/stream/TwitterStreamQuickstartDocSpec.scala
+++ b/akka-docs/rst/scala/code/docs/stream/TwitterStreamQuickstartDocSpec.scala
@@ -108,8 +108,8 @@ class TwitterStreamQuickstartDocSpec extends AkkaSpec {
 
   trait HiddenDefinitions {
     //#graph-dsl-broadcast
-    val writeAuthors: Sink[Author, Unit] = ???
-    val writeHashtags: Sink[Hashtag, Unit] = ???
+    val writeAuthors: Sink[Author, NotUsed] = ???
+    val writeHashtags: Sink[Hashtag, NotUsed] = ???
     //#graph-dsl-broadcast
   }
 
diff --git a/akka-docs/rst/scala/persistence.rst b/akka-docs/rst/scala/persistence.rst
index f2168a9a22..728d68f442 100644
--- a/akka-docs/rst/scala/persistence.rst
+++ b/akka-docs/rst/scala/persistence.rst
@@ -218,10 +218,10 @@ maximum stash capacity in the mailbox configuration::
 
 Note that the stash capacity is per actor. If you have many persistent actors, e.g. when using cluster sharding,
 you may need to define a small stash capacity to ensure that the total number of stashed messages in the system
-don't consume too much memory. Additionally, The persistent actor defines three strategies to handle failure when the 
+doesn't consume too much memory. Additionally, the persistent actor defines three strategies to handle failure when the 
 internal stash capacity is exceeded. The default overflow strategy is the ``ThrowOverflowExceptionStrategy``, which 
-discards the current received message and throws a ``StashOverflowException``, causing actor restart if default 
-supervision strategy is used. you can override the ``internalStashOverflowStrategy`` method to return 
+discards the current received message and throws a ``StashOverflowException``, causing actor restart if the default 
+supervision strategy is used. You can override the ``internalStashOverflowStrategy`` method to return 
 ``DiscardToDeadLetterStrategy`` or ``ReplyToStrategy`` for any "individual" persistent actor, or define the "default" 
 for all persistent actors by providing FQCN, which must be a subclass of ``StashOverflowStrategyConfigurator``, in the 
 persistence configuration::
@@ -232,7 +232,7 @@ persistence configuration::
 The ``DiscardToDeadLetterStrategy`` strategy also has a pre-packaged companion configurator 
 ``akka.persistence.DiscardConfigurator``.
 
-You can also query default strategy via the Akka persistence extension singleton::
+You can also query the default strategy via the Akka persistence extension singleton::
 
     Persistence(context.system).defaultInternalStashOverflowStrategy
 
diff --git a/akka-remote/src/test/scala/akka/remote/serialization/DaemonMsgCreateSerializerSpec.scala b/akka-remote/src/test/scala/akka/remote/serialization/DaemonMsgCreateSerializerSpec.scala
index 33168fc15d..058c591aca 100644
--- a/akka-remote/src/test/scala/akka/remote/serialization/DaemonMsgCreateSerializerSpec.scala
+++ b/akka-remote/src/test/scala/akka/remote/serialization/DaemonMsgCreateSerializerSpec.scala
@@ -4,16 +4,15 @@
 
 package akka.remote.serialization
 
-import language.postfixOps
-import akka.serialization.SerializationExtension
-import com.typesafe.config.ConfigFactory
-import akka.testkit.AkkaSpec
-import akka.actor.{ Actor, ActorRef, Address, Deploy, ExtendedActorSystem, OneForOneStrategy, Props, SupervisorStrategy }
+import akka.actor.{ Actor, ActorRef, ActorSystem, Address, Deploy, ExtendedActorSystem, OneForOneStrategy, Props, SupervisorStrategy }
 import akka.remote.{ DaemonMsgCreate, RemoteScope }
 import akka.routing.{ FromConfig, RoundRobinPool }
-import akka.util.ByteString
+import akka.serialization.SerializationExtension
+import akka.testkit.{ AkkaSpec, TestKit }
+import com.typesafe.config.ConfigFactory
 
 import scala.concurrent.duration._
+import scala.language.postfixOps
 
 object DaemonMsgCreateSerializerSpec {
 
@@ -81,33 +80,46 @@ class DaemonMsgCreateSerializerSpec extends AkkaSpec {
     }
 
     "deserialize the old wire format with just class and field for props parameters (if possible)" in {
-      val serializer = new DaemonMsgCreateSerializer(system.asInstanceOf[ExtendedActorSystem])
+      val system = ActorSystem("DaemonMsgCreateSerializer-old-wire-format", ConfigFactory.parseString(
+        """
+          # in 2.4 this is off by default, but in 2.5+ its on so we wouldn't
+          # get the right set of serializers (and since the old wire protocol doesn't
+          # contain serializer ids that will go unnoticed with unpleasant consequences)
+          akka.actor.enable-additional-serialization-bindings = off
+        """))
 
-      // the oldSnapshot was created with the version of DemonMsgCreateSerializer in Akka 2.4.17. See issue #22224.
-      // It was created with:
-      /*
+      try {
+        val serializer = new DaemonMsgCreateSerializer(system.asInstanceOf[ExtendedActorSystem])
+
+        // the oldSnapshot was created with the version of DemonMsgCreateSerializer in Akka 2.4.17. See issue #22224.
+        // It was created with:
+        /*
       import org.apache.commons.codec.binary.Hex.encodeHex
       val bytes = serializer.toBinary(
         DaemonMsgCreate(Props(classOf[MyActorWithParam], "a string"), Deploy.local, "/user/test", system.actorFor("/user")))
       println(String.valueOf(encodeHex(bytes)))
       */
 
-      val oldBytesHex =
-        "0a6a12020a001a48616b6b612e72656d6f74652e73657269616c697a6174696f" +
-          "6e2e4461656d6f6e4d736743726561746553657269616c697a6572537065632" +
-          "44d794163746f7257697468506172616d22086120737472696e672a106a6176" +
-          "612e6c616e672e537472696e67122f0a00222baced000573720016616b6b612" +
-          "e6163746f722e4c6f63616c53636f706524000000000000000102000078701a" +
-          "0a2f757365722f74657374222b0a29616b6b613a2f2f4461656d6f6e4d73674" +
-          "3726561746553657269616c697a6572537065632f75736572"
+        val oldBytesHex =
+          "0a7112020a001a48616b6b612e72656d6f74652e73657269616c697a617" +
+            "4696f6e2e4461656d6f6e4d736743726561746553657269616c697a6572" +
+            "53706563244d794163746f7257697468506172616d220faced000574000" +
+            "86120737472696e672a106a6176612e6c616e672e537472696e67122f0a" +
+            "00222baced000573720016616b6b612e6163746f722e4c6f63616c53636" +
+            "f706524000000000000000102000078701a0a2f757365722f7465737422" +
+            "2b0a29616b6b613a2f2f4461656d6f6e4d7367437265617465536572696" +
+            "16c697a6572537065632f75736572"
 
-      import org.apache.commons.codec.binary.Hex.decodeHex
-      val oldBytes = decodeHex(oldBytesHex.toCharArray)
-      val result = serializer.fromBinary(oldBytes, classOf[DaemonMsgCreate])
+        import org.apache.commons.codec.binary.Hex.decodeHex
+        val oldBytes = decodeHex(oldBytesHex.toCharArray)
+        val result = serializer.fromBinary(oldBytes, classOf[DaemonMsgCreate])
 
-      result match {
-        case dmc: DaemonMsgCreate ⇒
-          dmc.props.args should ===(Seq("a string": Any))
+        result match {
+          case dmc: DaemonMsgCreate ⇒
+            dmc.props.args should ===(Seq("a string": Any))
+        }
+      } finally {
+        TestKit.shutdownActorSystem(system)
       }
     }
 
diff --git a/akka-stream/src/main/scala/akka/stream/impl/CompletedPublishers.scala b/akka-stream/src/main/scala/akka/stream/impl/CompletedPublishers.scala
index 5f6293f251..585a43617e 100644
--- a/akka-stream/src/main/scala/akka/stream/impl/CompletedPublishers.scala
+++ b/akka-stream/src/main/scala/akka/stream/impl/CompletedPublishers.scala
@@ -3,12 +3,15 @@
  */
 package akka.stream.impl
 
-import org.reactivestreams.{ Subscriber, Publisher, Subscription }
+import akka.annotation.InternalApi
+import org.reactivestreams.{ Publisher, Subscriber, Subscription }
+
 import scala.concurrent.{ ExecutionContext, Promise }
 
 /**
  * INTERNAL API
  */
+@InternalApi
 private[akka] case object EmptyPublisher extends Publisher[Nothing] {
   import ReactiveStreamsCompliance._
   override def subscribe(subscriber: Subscriber[_ >: Nothing]): Unit =
diff --git a/akka-stream/src/main/scala/akka/stream/impl/Sources.scala b/akka-stream/src/main/scala/akka/stream/impl/Sources.scala
index 6f0443dea1..3db2be2bf1 100644
--- a/akka-stream/src/main/scala/akka/stream/impl/Sources.scala
+++ b/akka-stream/src/main/scala/akka/stream/impl/Sources.scala
@@ -16,6 +16,8 @@ import scala.concurrent.{ Future, Promise }
 import akka.Done
 import java.util.concurrent.CompletionStage
 
+import akka.annotation.InternalApi
+
 import scala.compat.java8.FutureConverters._
 import scala.util.Try
 import scala.util.control.NonFatal
@@ -396,3 +398,22 @@ final class LazySource[T, M](sourceFactory: () ⇒ Source[T, M]) extends GraphSt
   override def toString = "LazySource"
 }
 
+/** INTERNAL API */
+@InternalApi
+final object EmptySource extends GraphStage[SourceShape[Nothing]] {
+  val out = Outlet[Nothing]("EmptySource.out")
+  override val shape = SourceShape(out)
+
+  override protected def initialAttributes = DefaultAttributes.lazySource
+
+  override def createLogic(inheritedAttributes: Attributes): GraphStageLogic =
+    new GraphStageLogic(shape) with OutHandler {
+      override def preStart(): Unit = completeStage()
+      override def onPull(): Unit = completeStage()
+
+      setHandler(out, this)
+    }
+
+  override def toString = "EmptySource"
+}
+
diff --git a/akka-stream/src/main/scala/akka/stream/scaladsl/Source.scala b/akka-stream/src/main/scala/akka/stream/scaladsl/Source.scala
index ce2018d953..2e7a51a3c8 100644
--- a/akka-stream/src/main/scala/akka/stream/scaladsl/Source.scala
+++ b/akka-stream/src/main/scala/akka/stream/scaladsl/Source.scala
@@ -328,10 +328,8 @@ object Source {
    */
   def empty[T]: Source[T, NotUsed] = _empty
   private[this] val _empty: Source[Nothing, NotUsed] =
-    fromGraph(new PublisherSource[Nothing](
-      EmptyPublisher,
-      DefaultAttributes.emptySource,
-      shape("EmptySource")))
+    Source.fromGraph(EmptySource)
+
   /**
    * Create a `Source` which materializes a [[scala.concurrent.Promise]] which controls what element
    * will be emitted by the Source.
diff --git a/akka-typed/src/main/scala/akka/typed/Ask.scala b/akka-typed/src/main/scala/akka/typed/Ask.scala
index ac94a9cd77..e27e7c74ae 100644
--- a/akka-typed/src/main/scala/akka/typed/Ask.scala
+++ b/akka-typed/src/main/scala/akka/typed/Ask.scala
@@ -45,7 +45,9 @@ object AskPattern {
   }
 
   private class PromiseRef[U](target: ActorRef[_], untyped: InternalActorRef, timeout: Timeout) {
-    val (ref: ActorRef[U], future: Future[U], promiseRef: PromiseActorRef) =
+
+    // Note: _promiseRef mustn't have a type pattern, since it can be null
+    private[this] val (_ref: ActorRef[U], _future: Future[U], _promiseRef) =
       if (untyped.isTerminated)
         (
           adapter.ActorRefAdapter[U](untyped.provider.deadLetters),
@@ -59,6 +61,10 @@ object AskPattern {
         val b = adapter.ActorRefAdapter[U](a)
         (b, a.result.future.asInstanceOf[Future[U]], a)
       }
+
+    val ref: ActorRef[U] = _ref
+    val future: Future[U] = _future
+    val promiseRef: PromiseActorRef = _promiseRef
   }
 
   private def askUntyped[T, U](target: ActorRef[T], untyped: InternalActorRef, timeout: Timeout, f: ActorRef[U] ⇒ T): Future[U] = {
diff --git a/akka-typed/src/test/scala/akka/typed/AskSpec.scala b/akka-typed/src/test/scala/akka/typed/AskSpec.scala
new file mode 100644
index 0000000000..ada32b825c
--- /dev/null
+++ b/akka-typed/src/test/scala/akka/typed/AskSpec.scala
@@ -0,0 +1,82 @@
+/**
+ * Copyright (C) 2017 Lightbend Inc. <http://www.lightbend.com>
+ */
+package akka.typed
+
+import scala.concurrent.ExecutionContext
+import scala.concurrent.duration._
+
+import org.scalatest.concurrent.ScalaFutures
+
+import akka.util.Timeout
+import akka.pattern.AskTimeoutException
+
+import ScalaDSL._
+import AskPattern._
+
+object AskSpec {
+
+  sealed trait Msg
+  final case class Foo(s: String)(val replyTo: ActorRef[String]) extends Msg
+  final case class Stop(replyTo: ActorRef[Unit]) extends Msg
+}
+
+class AskSpec extends TypedSpec with ScalaFutures {
+
+  import AskSpec._
+
+  trait Common {
+
+    def system: ActorSystem[TypedSpec.Command]
+
+    implicit def executor: ExecutionContext =
+      system.executionContext
+
+    val behavior: Behavior[Msg] = Total[Msg] {
+      case foo @ Foo(_) ⇒
+        foo.replyTo ! "foo"
+        Same
+      case Stop(r) ⇒
+        r ! ()
+        Stopped
+    }
+
+    def `must fail the future if the actor is already terminated`(): Unit = {
+      val fut = for {
+        ref ← system ? TypedSpec.Create(behavior, "test1")
+        _ ← ref ? Stop
+        answer ← ref.?(Foo("bar"))(Timeout(1.second), implicitly)
+      } yield answer
+      (fut.recover { case _: AskTimeoutException ⇒ "" }).futureValue should ===("")
+    }
+
+    def `must succeed when the actor is alive`(): Unit = {
+      val fut = for {
+        ref ← system ? TypedSpec.Create(behavior, "test2")
+        answer ← ref ? Foo("bar")
+      } yield answer
+      fut.futureValue should ===("foo")
+    }
+  }
+
+  object `Ask pattern (native)` extends Common with NativeSystem
+
+  object `Ask pattern (adapted)` extends Common with AdaptedSystem {
+
+    import AskSpec._
+
+    /** See issue #19947 (MatchError with adapted ActorRef) */
+    def `must fail the future if the actor doesn't exist`(): Unit = {
+      val noSuchActor: ActorRef[Msg] = system match {
+        case adaptedSys: adapter.ActorSystemAdapter[_] ⇒
+          adapter.actorRefAdapter(adaptedSys.untyped.provider.resolveActorRef("/foo/bar"))
+        case _ ⇒
+          fail("this test must only run in an adapted actor system")
+      }
+      val fut = for {
+        answer ← noSuchActor.?(Foo("bar"))(Timeout(1.second), implicitly)
+      } yield answer
+      (fut.recover { case _: AskTimeoutException ⇒ "" }).futureValue should ===("")
+    }
+  }
+}
diff --git a/project/Dependencies.scala b/project/Dependencies.scala
index 565864e283..ca74ba1c35 100644
--- a/project/Dependencies.scala
+++ b/project/Dependencies.scala
@@ -17,7 +17,7 @@ object Dependencies {
   val sslConfigVersion = "0.2.1"
   val slf4jVersion = "1.7.23"
   val scalaXmlVersion = "1.0.6"
-  val aeronVersion = "1.2.0"
+  val aeronVersion = "1.2.3"
 
   val Versions = Seq(
     crossScalaVersions := Seq("2.11.8", "2.12.1"),
diff --git a/project/build.properties b/project/build.properties
index 43b8278c68..27e88aa115 100644
--- a/project/build.properties
+++ b/project/build.properties
@@ -1 +1 @@
-sbt.version=0.13.11
+sbt.version=0.13.13