diff --git a/all/src/main/scala/zhongl/stream/netty/all/package.scala b/all/src/main/scala/zhongl/stream/netty/all/package.scala
index a1a2604..c100212 100644
--- a/all/src/main/scala/zhongl/stream/netty/all/package.scala
+++ b/all/src/main/scala/zhongl/stream/netty/all/package.scala
@@ -24,10 +24,10 @@ import scala.reflect.ClassTag
 
 package object all {
 
-  implicit val sct: Transport[SocketChannel]               = findAvailable[SocketTransports, SocketChannel]
-  implicit val ssct: Transport[ServerSocketChannel]        = findAvailable[SocketTransports, ServerSocketChannel]
-  implicit val dsct: Transport[DomainSocketChannel]        = findAvailable[DomainSocketTransports, DomainSocketChannel]
-  implicit val sdsct: Transport[ServerDomainSocketChannel] = findAvailable[DomainSocketTransports, ServerDomainSocketChannel]
+  implicit def sct: Transport[SocketChannel]               = findAvailable[SocketTransports, SocketChannel]
+  implicit def ssct: Transport[ServerSocketChannel]        = findAvailable[SocketTransports, ServerSocketChannel]
+  implicit def dsct: Transport[DomainSocketChannel]        = findAvailable[DomainSocketTransports, DomainSocketChannel]
+  implicit def sdsct: Transport[ServerDomainSocketChannel] = findAvailable[DomainSocketTransports, ServerDomainSocketChannel]
 
   implicit private def stss: Seq[SocketTransports]        = Seq(EpollTransports, KQueueTransports, NioTransports)
   implicit private def dstss: Seq[DomainSocketTransports] = Seq(EpollTransports, KQueueTransports)
@@ -37,9 +37,7 @@ package object all {
       c: ClassTag[C],
       g: GetTransport[T, C]
   ): Transport[C] = {
-    s.find(_.available).map(g(_)).getOrElse {
-      throw new IllegalStateException(s"${c.runtimeClass.getName} is unavailable in your environment")
-    }
+    s.find(_.available).map(g(_)).getOrElse { Transport.dummy[C] }
   }
 
 }
diff --git a/all/src/test/scala/zhongl/stream/netty/all/ImplicitlySpec.scala b/all/src/test/scala/zhongl/stream/netty/all/ImplicitlySpec.scala
index 6185c5f..c5c1758 100644
--- a/all/src/test/scala/zhongl/stream/netty/all/ImplicitlySpec.scala
+++ b/all/src/test/scala/zhongl/stream/netty/all/ImplicitlySpec.scala
@@ -2,6 +2,7 @@ package zhongl.stream.netty.all
 
 import java.net._
 import java.nio.file.Files
+import scala.concurrent.Future
 import akka.actor.ActorSystem
 import akka.stream.{ActorMaterializer, Materializer}
 import akka.stream.scaladsl.{Flow, Sink, Source}
@@ -45,7 +46,7 @@ class ImplicitlySpec extends TestKit(ActorSystem("implicitly")) with AsyncWordSp
       } else if (Epoll.isAvailable) {
         cc shouldBe classOf[EpollDomainSocketChannel]
       } else {
-        assertThrows[IllegalStateException](cc)
+        cc shouldBe classOf[DomainSocketChannel]
       }
     }
 
@@ -62,7 +63,10 @@ class ImplicitlySpec extends TestKit(ActorSystem("implicitly")) with AsyncWordSp
     }
   }
 
-  private def runEcho[C <: DuplexChannel, S <: ServerChannel](address: SocketAddress)(implicit t: Transport[C], s: Transport[S]) = {
+  private def runEcho[C <: DuplexChannel, S <: ServerChannel](
+      address: SocketAddress
+  )(implicit t: Transport[C], s: Transport[S]): Future[Assertion] = {
+    if (t.isInstanceOf[Transport.Dummy[C]]) return Future(Assertions.succeed)
     Netty().bindAndHandle[S](Flow[ByteString].map(identity), address).flatMap { sb =>
       val msg = ByteString("a")
       Source
@@ -73,5 +77,5 @@ class ImplicitlySpec extends TestKit(ActorSystem("implicitly")) with AsyncWordSp
         .flatMap(a => sb.unbind().map(_ => a))
     }
   }
-  override protected def afterAll(): Unit                                                                                        = TestKit.shutdownActorSystem(system)
+  override protected def afterAll(): Unit = TestKit.shutdownActorSystem(system)
 }
diff --git a/build.sbt b/build.sbt
index faa60f9..0a1ae95 100644
--- a/build.sbt
+++ b/build.sbt
@@ -9,7 +9,7 @@ inThisBuild(
       "-encoding",
       "UTF-8"
     ),
-    crossScalaVersions := Seq(scalaVersion.value, "2.12.15"),
+    crossScalaVersions := Seq(scalaVersion.value, "2.12.18"),
     organization       := "com.github.zhongl",
     homepage           := Some(url("https://github.com/hanabix/akka-stream-netty")),
     licenses           := List(
diff --git a/core/src/main/scala/zhongl/stream/netty/Transport.scala b/core/src/main/scala/zhongl/stream/netty/Transport.scala
index b9974cc..135e393 100644
--- a/core/src/main/scala/zhongl/stream/netty/Transport.scala
+++ b/core/src/main/scala/zhongl/stream/netty/Transport.scala
@@ -33,4 +33,12 @@ object Transport {
     override def channel = implicitly[ClassTag[C]].runtimeClass.asInstanceOf[Class[C]]
     override def group   = _group
   }
+
+  def dummy[C <: Channel: ClassTag] = new Dummy(implicitly[ClassTag[C]])
+
+  class Dummy[C <: Channel](c: ClassTag[C]) extends Transport[C] {
+    override def channel: Class[_ <: C] = c.runtimeClass.asInstanceOf[Class[C]]
+    override def group: EventLoopGroup  = throw new UnsupportedOperationException(s"${channel.getName} is unavailable in your environment")
+
+  }
 }