diff --git a/akka-actor/src/main/mima-filters/2.5.x.backwards.excludes/2.5.26-vs-2.6.0-RC1.excludes b/akka-actor/src/main/mima-filters/2.5.x.backwards.excludes/2.5.26-vs-2.6.0-RC1.excludes
new file mode 100644
index 0000000000..137e6ba154
--- /dev/null
+++ b/akka-actor/src/main/mima-filters/2.5.x.backwards.excludes/2.5.26-vs-2.6.0-RC1.excludes
@@ -0,0 +1,2 @@
+# Diverging but internal
+ProblemFilters.exclude[IncompatibleSignatureProblem]("akka.actor.FSM#Timer.unapply")
\ No newline at end of file
diff --git a/akka-actor/src/main/scala/akka/actor/TypedActor.scala b/akka-actor/src/main/scala/akka/actor/TypedActor.scala
index 43da24ea43..b0662da676 100644
--- a/akka-actor/src/main/scala/akka/actor/TypedActor.scala
+++ b/akka-actor/src/main/scala/akka/actor/TypedActor.scala
@@ -128,10 +128,6 @@ object TypedActor extends ExtensionId[TypedActorExtension] with ExtensionIdProvi
   @silent("deprecated")
   def get(context: ActorContext): TypedActorFactory = apply(context)
 
-  @deprecated("Use 'akka.actor.typed' API.", since = "2.6.0")
-  @silent("deprecated")
-  override def apply(system: ActorSystem): TypedActorExtension = super.apply(system)
-
   /**
    * This class represents a Method call, and has a reference to the Method to be called and the parameters to supply
    * It's sent to the ActorRef backing the TypedActor and can be serialized and deserialized
diff --git a/akka-persistence/src/main/mima-filters/2.5.x.backwards.excludes/2.5.26-vs-2.6.0-RC1.excludes b/akka-persistence/src/main/mima-filters/2.5.x.backwards.excludes/2.5.26-vs-2.6.0-RC1.excludes
new file mode 100644
index 0000000000..8b27e94a6b
--- /dev/null
+++ b/akka-persistence/src/main/mima-filters/2.5.x.backwards.excludes/2.5.26-vs-2.6.0-RC1.excludes
@@ -0,0 +1,2 @@
+# Diverging but internal
+ProblemFilters.exclude[IncompatibleSignatureProblem]("akka.persistence.fsm.PersistentFSM#Timer.unapply")
\ No newline at end of file
diff --git a/akka-remote/src/main/mima-filters/2.5.x.backwards.excludes/2.5.26-vs-2.6.0-RC1.excludes b/akka-remote/src/main/mima-filters/2.5.x.backwards.excludes/2.5.26-vs-2.6.0-RC1.excludes
new file mode 100644
index 0000000000..9cdfc07c4c
--- /dev/null
+++ b/akka-remote/src/main/mima-filters/2.5.x.backwards.excludes/2.5.26-vs-2.6.0-RC1.excludes
@@ -0,0 +1,4 @@
+# Diverging but internal
+ProblemFilters.exclude[IncompatibleSignatureProblem]("akka.remote.artery.Association#OutboundStreamMatValues.unapply")
+ProblemFilters.exclude[IncompatibleSignatureProblem]("akka.remote.transport.AkkaPduCodec#Message.unapply")
+ProblemFilters.exclude[IncompatibleSignatureProblem]("akka.remote.EndpointManager#Send.unapply")
\ No newline at end of file
diff --git a/akka-stream/src/main/mima-filters/2.5.x.backwards.excludes/2.5.26-vs-2.6.0-RC1.excludes b/akka-stream/src/main/mima-filters/2.5.x.backwards.excludes/2.5.26-vs-2.6.0-RC1.excludes
new file mode 100644
index 0000000000..fce14e5980
--- /dev/null
+++ b/akka-stream/src/main/mima-filters/2.5.x.backwards.excludes/2.5.26-vs-2.6.0-RC1.excludes
@@ -0,0 +1,3 @@
+# Diverging, only companion (which yields class) but ever emitted and not meant for user extension
+# so no user code compiled against 2.5 will ever refer to it
+ProblemFilters.exclude[IncompatibleTemplateDefProblem]("akka.stream.SubscriptionWithCancelException")
\ No newline at end of file
diff --git a/akka-stream/src/main/scala/akka/stream/SubscriptionWithCancelException.scala b/akka-stream/src/main/scala/akka/stream/SubscriptionWithCancelException.scala
index 24ec4dcb89..43efbd1e6e 100644
--- a/akka-stream/src/main/scala/akka/stream/SubscriptionWithCancelException.scala
+++ b/akka-stream/src/main/scala/akka/stream/SubscriptionWithCancelException.scala
@@ -14,7 +14,10 @@ import scala.util.control.NoStackTrace
  *
  * Subscribers can check for this trait and use its `cancel(cause)` method instead of the regular
  * cancel method to pass a cancellation cause.
+ *
+ * Not for user extension.
  */
+@DoNotInherit
 trait SubscriptionWithCancelException extends Subscription {
   final override def cancel() = cancel(SubscriptionWithCancelException.NoMoreElementsNeeded)
   def cancel(cause: Throwable): Unit
diff --git a/project/MiMa.scala b/project/MiMa.scala
index 423735798f..6b2f869003 100644
--- a/project/MiMa.scala
+++ b/project/MiMa.scala
@@ -12,7 +12,7 @@ import com.typesafe.tools.mima.plugin.MimaPlugin.autoImport._
 
 object MiMa extends AutoPlugin {
 
-  private val latestPatchOf25 = 25
+  private val latestPatchOf25 = 26
   // No 2.6 has been released yet. Update to '0' after releasing 2.6.0
   private val latestPatchOf26 = -1