diff --git a/src/context.rs b/src/context.rs
index 19a2b4a0c..28cf5d7d9 100644
--- a/src/context.rs
+++ b/src/context.rs
@@ -6,9 +6,9 @@ use futures::unsync::oneshot;
 use smallvec::SmallVec;
 
 use actix::{Actor, ActorState, ActorContext, AsyncContext,
-            Address, SyncAddress, Handler, ResponseType, MessageResult, SpawnHandle};
+            Addr, Handler, ResponseType, MessageResult, SpawnHandle, Syn, Unsync};
 use actix::fut::ActorFuture;
-use actix::dev::{ContextImpl, Envelope, ToEnvelope, RemoteEnvelope};
+use actix::dev::{ContextImpl, ToEnvelope, RemoteEnvelope};
 
 use body::{Body, Binary};
 use error::{Error, ErrorInternalServerError};
@@ -83,12 +83,12 @@ impl<A, S> AsyncContext<A> for HttpContext<A, S> where A: Actor<Context=Self>
     }
     #[doc(hidden)]
     #[inline]
-    fn local_address(&mut self) -> Address<A> {
+    fn unsync_address(&mut self) -> Addr<Unsync<A>> {
         self.inner.unsync_address()
     }
     #[doc(hidden)]
     #[inline]
-    fn sync_address(&mut self) -> SyncAddress<A> {
+    fn sync_address(&mut self) -> Addr<Syn<A>> {
         self.inner.sync_address()
     }
 }
@@ -205,15 +205,12 @@ impl<A, S> ActorHttpContext for HttpContext<A, S> where A: Actor<Context=Self>,
     }
 }
 
-impl<A, S> ToEnvelope<A> for HttpContext<A, S>
-    where A: Actor<Context=HttpContext<A, S>>,
+impl<A, M, S> ToEnvelope<Syn<A>, M> for HttpContext<A, S>
+    where A: Actor<Context=HttpContext<A, S>> + Handler<M>,
+          M: ResponseType + Send + 'static, M::Item: Send, M::Error: Send,
 {
-    #[inline]
-    fn pack<M>(msg: M, tx: Option<Sender<MessageResult<M>>>) -> Envelope<A>
-        where A: Handler<M>,
-              M: ResponseType + Send + 'static, M::Item: Send, M::Error: Send
-    {
-        RemoteEnvelope::envelope(msg, tx).into()
+    fn pack(msg: M, tx: Option<Sender<MessageResult<M>>>) -> Syn<A> {
+        Syn::new(Box::new(RemoteEnvelope::envelope(msg, tx)))
     }
 }
 
diff --git a/src/pipeline.rs b/src/pipeline.rs
index d1328ad99..babd92199 100644
--- a/src/pipeline.rs
+++ b/src/pipeline.rs
@@ -739,7 +739,7 @@ mod tests {
 
             let req = HttpRequest::default();
             let mut ctx = HttpContext::new(req.clone(), MyActor);
-            let addr: Address<_> = ctx.address();
+            let addr: Addr<Unsync<_>> = ctx.address();
             let mut info = PipelineInfo::new(req);
             info.context = Some(Box::new(ctx));
             let mut state = Completed::<(), Inner<()>>::init(&mut info).completed().unwrap();
diff --git a/src/server/srv.rs b/src/server/srv.rs
index 79f90774d..3cd6da122 100644
--- a/src/server/srv.rs
+++ b/src/server/srv.rs
@@ -36,12 +36,12 @@ pub struct HttpServer<H> where H: IntoHttpHandler + 'static
     host: Option<String>,
     keep_alive: Option<u64>,
     factory: Arc<Fn() -> Vec<H> + Send + Sync>,
-    workers: Vec<SyncAddress<Worker<H::Handler>>>,
+    workers: Vec<Addr<Syn<Worker<H::Handler>>>>,
     sockets: HashMap<net::SocketAddr, net::TcpListener>,
     accept: Vec<(mio::SetReadiness, sync_mpsc::Sender<Command>)>,
     exit: bool,
     shutdown_timeout: u16,
-    signals: Option<SyncAddress<signal::ProcessSignals>>,
+    signals: Option<Addr<Syn<signal::ProcessSignals>>>,
     no_signals: bool,
 }
 
@@ -146,7 +146,7 @@ impl<H> HttpServer<H> where H: IntoHttpHandler + 'static
     }
 
     /// Set alternative address for `ProcessSignals` actor.
-    pub fn signals(mut self, addr: SyncAddress<signal::ProcessSignals>) -> Self {
+    pub fn signals(mut self, addr: Addr<Syn<signal::ProcessSignals>>) -> Self {
         self.signals = Some(addr);
         self
     }
@@ -227,7 +227,7 @@ impl<H> HttpServer<H> where H: IntoHttpHandler + 'static
     }
 
     // subscribe to os signals
-    fn subscribe_to_signals(&self) -> Option<SyncAddress<signal::ProcessSignals>> {
+    fn subscribe_to_signals(&self) -> Option<Addr<Syn<signal::ProcessSignals>>> {
         if !self.no_signals {
             if let Some(ref signals) = self.signals {
                 Some(signals.clone())
@@ -269,7 +269,7 @@ impl<H: IntoHttpHandler> HttpServer<H>
     ///    let _ = sys.run();  // <- Run actix system, this method actually starts all async processes
     /// }
     /// ```
-    pub fn start(mut self) -> SyncAddress<Self>
+    pub fn start(mut self) -> Addr<Syn<Self>>
     {
         if self.sockets.is_empty() {
             panic!("HttpServer::bind() has to be called before start()");
@@ -288,9 +288,9 @@ impl<H: IntoHttpHandler> HttpServer<H>
 
             // start http server actor
             let signals = self.subscribe_to_signals();
-            let addr: SyncAddress<_> = Actor::start(self);
+            let addr: Addr<Syn<_>> = Actor::start(self);
             signals.map(|signals| signals.send(
-                signal::Subscribe(addr.clone().into())));
+                signal::Subscribe(addr.clone().subscriber())));
             addr
         }
     }
@@ -407,7 +407,7 @@ impl<H: IntoHttpHandler> HttpServer<H>
     /// Start listening for incoming connections from a stream.
     ///
     /// This method uses only one thread for handling incoming connections.
-    pub fn start_incoming<T, A, S>(mut self, stream: S, secure: bool) -> SyncAddress<Self>
+    pub fn start_incoming<T, A, S>(mut self, stream: S, secure: bool) -> Addr<Syn<Self>>
         where S: Stream<Item=(T, A), Error=io::Error> + 'static,
               T: AsyncRead + AsyncWrite + 'static,
               A: 'static
@@ -435,7 +435,7 @@ impl<H: IntoHttpHandler> HttpServer<H>
 
         // start server
         let signals = self.subscribe_to_signals();
-        let addr: SyncAddress<_> = HttpServer::create(move |ctx| {
+        let addr: Addr<Syn<_>> = HttpServer::create(move |ctx| {
             ctx.add_message_stream(
                 stream
                     .map_err(|_| ())
@@ -443,7 +443,7 @@ impl<H: IntoHttpHandler> HttpServer<H>
             self
         });
         signals.map(|signals| signals.send(
-            signal::Subscribe(addr.clone().into())));
+            signal::Subscribe(addr.clone().subscriber())));
         addr
     }
 }
diff --git a/src/test.rs b/src/test.rs
index bc8da075a..c98929f0a 100644
--- a/src/test.rs
+++ b/src/test.rs
@@ -6,7 +6,7 @@ use std::sync::mpsc;
 use std::str::FromStr;
 use std::collections::HashMap;
 
-use actix::{Arbiter, SyncAddress, System, SystemRunner, msgs};
+use actix::{Arbiter, Addr, Syn, System, SystemRunner, msgs};
 use cookie::Cookie;
 use http::{Uri, Method, Version, HeaderMap, HttpTryFrom};
 use http::header::{HeaderName, HeaderValue};
@@ -56,7 +56,7 @@ pub struct TestServer {
     addr: net::SocketAddr,
     thread: Option<thread::JoinHandle<()>>,
     system: SystemRunner,
-    server_sys: SyncAddress<System>,
+    server_sys: Addr<Syn<System>>,
 }
 
 impl TestServer {
diff --git a/src/ws/client.rs b/src/ws/client.rs
index 8b4837c12..7800ab02f 100644
--- a/src/ws/client.rs
+++ b/src/ws/client.rs
@@ -103,7 +103,7 @@ pub struct WsClient {
     http_err: Option<HttpError>,
     origin: Option<HeaderValue>,
     protocols: Option<String>,
-    conn: Address<ClientConnector>,
+    conn: Addr<Unsync<ClientConnector>>,
 }
 
 impl WsClient {
@@ -114,7 +114,7 @@ impl WsClient {
     }
 
     /// Create new websocket connection with custom `ClientConnector`
-    pub fn with_connector<S: AsRef<str>>(uri: S, conn: Address<ClientConnector>) -> WsClient {
+    pub fn with_connector<S: AsRef<str>>(uri: S, conn: Addr<Unsync<ClientConnector>>) -> WsClient {
         let mut cl = WsClient {
             request: ClientRequest::build(),
             err: None,
diff --git a/src/ws/context.rs b/src/ws/context.rs
index 835c1774e..1eb78c7e5 100644
--- a/src/ws/context.rs
+++ b/src/ws/context.rs
@@ -5,9 +5,9 @@ use futures::unsync::oneshot;
 use smallvec::SmallVec;
 
 use actix::{Actor, ActorState, ActorContext, AsyncContext,
-            Address, SyncAddress, Handler, ResponseType, SpawnHandle, MessageResult};
+            Addr, Handler, ResponseType, SpawnHandle, MessageResult, Syn, Unsync};
 use actix::fut::ActorFuture;
-use actix::dev::{ContextImpl, Envelope, ToEnvelope, RemoteEnvelope};
+use actix::dev::{ContextImpl, ToEnvelope, RemoteEnvelope};
 
 use body::{Body, Binary};
 use error::{Error, ErrorInternalServerError};
@@ -67,13 +67,13 @@ impl<A, S> AsyncContext<A> for WebsocketContext<A, S> where A: Actor<Context=Sel
 
     #[doc(hidden)]
     #[inline]
-    fn local_address(&mut self) -> Address<A> {
+    fn unsync_address(&mut self) -> Addr<Unsync<A>> {
         self.inner.unsync_address()
     }
 
     #[doc(hidden)]
     #[inline]
-    fn sync_address(&mut self) -> SyncAddress<A> {
+    fn sync_address(&mut self) -> Addr<Syn<A>> {
         self.inner.sync_address()
     }
 }
@@ -217,14 +217,12 @@ impl<A, S> ActorHttpContext for WebsocketContext<A, S> where A: Actor<Context=Se
     }
 }
 
-impl<A, S> ToEnvelope<A> for WebsocketContext<A, S>
-    where A: Actor<Context=WebsocketContext<A, S>>,
+impl<A, M, S> ToEnvelope<Syn<A>, M> for WebsocketContext<A, S>
+    where A: Actor<Context=WebsocketContext<A, S>> + Handler<M>,
+          M: ResponseType + Send + 'static, M::Item: Send, M::Error: Send,
 {
-    #[inline]
-    fn pack<M>(msg: M, tx: Option<Sender<MessageResult<M>>>) -> Envelope<A>
-        where A: Handler<M>,
-              M: ResponseType + Send + 'static, M::Item: Send, M::Error: Send {
-        RemoteEnvelope::envelope(msg, tx).into()
+    fn pack(msg: M, tx: Option<Sender<MessageResult<M>>>) -> Syn<A> {
+        Syn::new(Box::new(RemoteEnvelope::envelope(msg, tx)))
     }
 }