diff --git a/.circleci/config.yml b/.circleci/config.yml
index d9828e7b..bc5c76a8 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -45,19 +45,19 @@ jobs:
       - when:
           condition: << parameters.test-unstable >>
           steps:
-#            - run:
-#                name: Beta
-#                command: |
-#                  rustup toolchain install beta
-#                  cargo +beta test
             - run:
                 name: Nightly
                 command: |
                   rustup toolchain install nightly
                   cargo +nightly test
+            - run:
+                name: Beta
+                command: |
+                  rustup toolchain install beta
+                  cargo +beta test
             - run:
                 name: Nightly SSL
-                command: cargo +nightly test
+                command: cargo +beta test
                 environment:
                   SSL: 1
 
diff --git a/Cargo.toml b/Cargo.toml
index c060e255..792b6b71 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -19,21 +19,21 @@ crossbeam = "0.7"
 failure = "0.1"
 failure_derive = "0.1"
 fnv = "1"
-futures-core-preview = "0.3.0-alpha.18"
-futures-util-preview = "0.3.0-alpha.18"
-futures-sink-preview = "0.3.0-alpha.18"
+futures-core-preview = "=0.3.0-alpha.19"
+futures-util-preview = "=0.3.0-alpha.19"
+futures-sink-preview = "=0.3.0-alpha.19"
 mio-named-pipes = "0.1.6"
 mysql_common = "0.18"
 native-tls = "0.2"
 percent-encoding = "2.1.0"
-pin-project = { version = "0.4.0-alpha.11", features = ["project_attr"] }
+pin-project = "0.4.0"
 regex = "1"
 serde = "1"
 serde_json = "1"
 # we only need rt-full for tokio::spawn
-tokio = { version = "0.2.0-alpha.5", default-features = false, features = ["codec", "io", "net", "sync", "fs", "rt-full"] }
-tokio-tls = "0.3.0-alpha.5"
-tokio-net = "0.2.0-alpha.5"
+tokio = { version = "=0.2.0-alpha.6", default-features = false, features = ["codec", "io", "net", "sync", "fs", "rt-full"] }
+tokio-tls = "=0.3.0-alpha.6"
+tokio-net = "=0.2.0-alpha.6"
 twox-hash = "1"
 url = "2.1"
 
diff --git a/appveyor.yml b/appveyor.yml
index 19af3fdb..215435f2 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -12,14 +12,14 @@ environment:
       PATH: C:\msys64\mingw64\bin\;c:\rust\bin;%PATH%
     - TARGET: nightly-i686-pc-windows-gnu
       PATH: C:\msys64\mingw32\bin\;c:\rust\bin;%PATH%
-#    - TARGET: beta-x86_64-pc-windows-msvc
-#      PATH: C:\msys64\mingw64\bin\;c:\rust\bin;%PATH%
-#    - TARGET: beta-i686-pc-windows-msvc
-#      PATH: C:\msys64\mingw32\bin\;c:\rust\bin;%PATH%
-#    - TARGET: beta-x86_64-pc-windows-gnu
-#      PATH: C:\msys64\mingw64\bin\;c:\rust\bin;%PATH%
-#    - TARGET: beta-i686-pc-windows-gnu
-#      PATH: C:\msys64\mingw32\bin\;c:\rust\bin;%PATH%
+    - TARGET: beta-x86_64-pc-windows-msvc
+      PATH: C:\msys64\mingw64\bin\;c:\rust\bin;%PATH%
+    - TARGET: beta-i686-pc-windows-msvc
+      PATH: C:\msys64\mingw32\bin\;c:\rust\bin;%PATH%
+    - TARGET: beta-x86_64-pc-windows-gnu
+      PATH: C:\msys64\mingw64\bin\;c:\rust\bin;%PATH%
+    - TARGET: beta-i686-pc-windows-gnu
+      PATH: C:\msys64\mingw32\bin\;c:\rust\bin;%PATH%
 #    - TARGET: 1.34.0-x86_64-pc-windows-msvc
 #      PATH: C:\msys64\mingw64\bin\;c:\rust\bin;%PATH%
 #    - TARGET: 1.34.0-i686-pc-windows-msvc
diff --git a/src/connection_like/read_packet.rs b/src/connection_like/read_packet.rs
index 5cde4922..bb8d5077 100644
--- a/src/connection_like/read_packet.rs
+++ b/src/connection_like/read_packet.rs
@@ -40,7 +40,7 @@ impl<T: ConnectionLike> ReadPacket<T> {
 impl<T: ConnectionLike> Future for ReadPacket<T> {
     type Output = Result<(T, RawPacket)>;
 
-    fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
+    fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
         let this = self.project();
         let (packet_opt, stream) = ready!(this.fut.poll(cx));
         let packet_opt = packet_opt.transpose()?;
diff --git a/src/connection_like/write_packet.rs b/src/connection_like/write_packet.rs
index 747fc8ac..dbb51375 100644
--- a/src/connection_like/write_packet.rs
+++ b/src/connection_like/write_packet.rs
@@ -39,7 +39,7 @@ impl<T: ConnectionLike> WritePacket<T> {
 impl<T: ConnectionLike> Future for WritePacket<T> {
     type Output = Result<T>;
 
-    fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
+    fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
         let this = self.project();
         let (stream, seq_id) = ready!(this.fut.poll(cx))?;
         let mut conn_like = this.conn_like.take().unwrap().return_stream(stream);
diff --git a/src/io/async_tls.rs b/src/io/async_tls.rs
index 99445cda..ba0608c4 100644
--- a/src/io/async_tls.rs
+++ b/src/io/async_tls.rs
@@ -45,7 +45,7 @@ where
     S: AsyncRead + AsyncWrite + Unpin,
 {
     fn poll_read(
-        mut self: Pin<&mut Self>,
+        self: Pin<&mut Self>,
         cx: &mut Context,
         buf: &mut [u8],
     ) -> Poll<Result<usize, IoError>> {
@@ -57,7 +57,7 @@ where
     }
 
     fn poll_read_buf<B>(
-        mut self: Pin<&mut Self>,
+        self: Pin<&mut Self>,
         cx: &mut Context,
         buf: &mut B,
     ) -> Poll<Result<usize, IoError>>
@@ -73,16 +73,16 @@ where
     S: AsyncRead + AsyncWrite + Unpin,
 {
     fn poll_write(
-        mut self: Pin<&mut Self>,
+        self: Pin<&mut Self>,
         cx: &mut Context,
         buf: &[u8],
     ) -> Poll<Result<usize, IoError>> {
         self.project().inner.poll_write(cx, buf)
     }
-    fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<(), IoError>> {
+    fn poll_flush(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<(), IoError>> {
         self.project().inner.poll_flush(cx)
     }
-    fn poll_shutdown(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<(), IoError>> {
+    fn poll_shutdown(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<(), IoError>> {
         self.project().inner.poll_shutdown(cx)
     }
 }
diff --git a/src/io/mod.rs b/src/io/mod.rs
index 8504d1bc..09902de8 100644
--- a/src/io/mod.rs
+++ b/src/io/mod.rs
@@ -127,7 +127,7 @@ impl From<self::async_tls::TlsStream<TcpStream>> for Endpoint {
 impl AsyncRead for Endpoint {
     #[project]
     fn poll_read(
-        mut self: Pin<&mut Self>,
+        self: Pin<&mut Self>,
         cx: &mut Context,
         buf: &mut [u8],
     ) -> Poll<StdResult<usize, tokio::io::Error>> {
@@ -149,7 +149,7 @@ impl AsyncRead for Endpoint {
 
     #[project]
     fn poll_read_buf<B>(
-        mut self: Pin<&mut Self>,
+        self: Pin<&mut Self>,
         cx: &mut Context,
         buf: &mut B,
     ) -> Poll<StdResult<usize, tokio::io::Error>>
@@ -168,7 +168,7 @@ impl AsyncRead for Endpoint {
 impl AsyncWrite for Endpoint {
     #[project]
     fn poll_write(
-        mut self: Pin<&mut Self>,
+        self: Pin<&mut Self>,
         cx: &mut Context,
         buf: &[u8],
     ) -> Poll<StdResult<usize, tokio::io::Error>> {
@@ -181,10 +181,7 @@ impl AsyncWrite for Endpoint {
     }
 
     #[project]
-    fn poll_flush(
-        mut self: Pin<&mut Self>,
-        cx: &mut Context,
-    ) -> Poll<StdResult<(), tokio::io::Error>> {
+    fn poll_flush(self: Pin<&mut Self>, cx: &mut Context) -> Poll<StdResult<(), tokio::io::Error>> {
         #[project]
         match self.project() {
             Endpoint::Plain(stream) => stream.poll_flush(cx),
@@ -195,7 +192,7 @@ impl AsyncWrite for Endpoint {
 
     #[project]
     fn poll_shutdown(
-        mut self: Pin<&mut Self>,
+        self: Pin<&mut Self>,
         cx: &mut Context,
     ) -> Poll<StdResult<(), tokio::io::Error>> {
         #[project]
diff --git a/src/io/socket.rs b/src/io/socket.rs
index 9fa81bc9..99061163 100644
--- a/src/io/socket.rs
+++ b/src/io/socket.rs
@@ -49,7 +49,7 @@ impl Socket {
 
 impl AsyncRead for Socket {
     fn poll_read(
-        mut self: Pin<&mut Self>,
+        self: Pin<&mut Self>,
         cx: &mut Context,
         buf: &mut [u8],
     ) -> Poll<Result<usize, Error>> {
@@ -61,7 +61,7 @@ impl AsyncRead for Socket {
     }
 
     fn poll_read_buf<B>(
-        mut self: Pin<&mut Self>,
+        self: Pin<&mut Self>,
         cx: &mut Context,
         buf: &mut B,
     ) -> Poll<Result<usize, Error>>
@@ -74,16 +74,16 @@ impl AsyncRead for Socket {
 
 impl AsyncWrite for Socket {
     fn poll_write(
-        mut self: Pin<&mut Self>,
+        self: Pin<&mut Self>,
         cx: &mut Context,
         buf: &[u8],
     ) -> Poll<Result<usize, Error>> {
         self.project().inner.poll_write(cx, buf)
     }
-    fn poll_flush(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<(), Error>> {
+    fn poll_flush(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<(), Error>> {
         self.project().inner.poll_flush(cx)
     }
-    fn poll_shutdown(mut self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<(), Error>> {
+    fn poll_shutdown(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Result<(), Error>> {
         self.project().inner.poll_shutdown(cx)
     }
 }