diff --git a/.gitmodules b/.gitmodules
index 0a7fc93..b9069a0 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,3 +1,6 @@
 [submodule "h3"]
 	path = h3
 	url = git@github.com:junkurihara/h3.git
+[submodule "quinn"]
+	path = quinn
+	url = git@github.com:junkurihara/quinn.git
diff --git a/Cargo.toml b/Cargo.toml
index 166b06c..8da0a8f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -43,24 +43,27 @@ hyper = { version = "0.14.25", default-features = false, features = [
   "http2",
   "stream",
 ] }
-hyper-rustls = { version = "0.23.2", default-features = false, features = [
+hyper-rustls = { version = "0.24.0", default-features = false, features = [
   "tokio-runtime",
   "webpki-tokio",
   "http1",
   "http2",
 ] }
-tokio-rustls = { version = "0.23.4", features = ["early-data"] }
+tokio-rustls = { version = "0.24.0", features = ["early-data"] }
 rustls-pemfile = "1.0.2"
-rustls = { version = "0.20.8", default-features = false }
+rustls = { version = "0.21.0", default-features = false }
+webpki = "0.22.0"
 
 # logging
 tracing = { version = "0.1.37" }
 tracing-subscriber = { version = "0.3.16", features = ["env-filter"] }
 
 # http/3
-quinn = { version = "0.9.3", optional = true }
+# quinn = { version = "0.9.3", optional = true }
+quinn = { path = "./quinn/quinn", optional = true } # Tentative to support rustls-0.21
 h3 = { path = "./h3/h3/", optional = true }
-h3-quinn = { path = "./h3/h3-quinn/", optional = true }
+# h3-quinn = { path = "./h3/h3-quinn/", optional = true }
+h3-quinn = { path = "./h3-quinn/", optional = true } # Tentative to support rustls-0.21
 
 
 [target.'cfg(not(target_env = "msvc"))'.dependencies]
diff --git a/h3-quinn/Cargo.toml b/h3-quinn/Cargo.toml
new file mode 100644
index 0000000..5f7661a
--- /dev/null
+++ b/h3-quinn/Cargo.toml
@@ -0,0 +1,21 @@
+[package]
+name = "h3-quinn"
+version = "0.0.1"
+rust-version = "1.59"
+authors = ["Jean-Christophe BEGUE <jc.begue@pm.me>"]
+edition = "2018"
+documentation = "https://docs.rs/h3-quinn"
+repository = "https://github.com/hyperium/h3"
+readme = "../README.md"
+description = "QUIC transport implementation based on Quinn."
+keywords = ["http3", "quic", "h3"]
+categories = ["network-programming", "web-programming"]
+license = "MIT"
+
+[dependencies]
+h3 = { version = "0.0.1", path = "../h3/h3" }
+bytes = "1"
+quinn = { path = "../quinn/quinn/", default-features = false }
+quinn-proto = { path = "../quinn/quinn-proto/", default-features = false }
+tokio-util = { version = "0.7.7" }
+futures = { version = "0.3.27" }
diff --git a/h3-quinn/src/lib.rs b/h3-quinn/src/lib.rs
new file mode 100644
index 0000000..62d84d8
--- /dev/null
+++ b/h3-quinn/src/lib.rs
@@ -0,0 +1,559 @@
+//! QUIC Transport implementation with Quinn
+//!
+//! This module implements QUIC traits with Quinn.
+#![deny(missing_docs)]
+
+use std::{
+    convert::TryInto,
+    fmt::{self, Display},
+    future::Future,
+    sync::Arc,
+    task::{self, Poll},
+};
+
+use bytes::{Buf, Bytes};
+
+use futures::{
+    ready,
+    stream::{self, BoxStream},
+    StreamExt,
+};
+pub use quinn::{
+    self, crypto::Session, AcceptBi, AcceptUni, Endpoint, OpenBi, OpenUni, VarInt, WriteError,
+};
+
+use h3::quic::{self, Error, StreamId, WriteBuf};
+use tokio_util::sync::ReusableBoxFuture;
+
+/// A QUIC connection backed by Quinn
+///
+/// Implements a [`quic::Connection`] backed by a [`quinn::Connection`].
+pub struct Connection {
+    conn: quinn::Connection,
+    incoming_bi: BoxStream<'static, <AcceptBi<'static> as Future>::Output>,
+    opening_bi: Option<BoxStream<'static, <OpenBi<'static> as Future>::Output>>,
+    incoming_uni: BoxStream<'static, <AcceptUni<'static> as Future>::Output>,
+    opening_uni: Option<BoxStream<'static, <OpenUni<'static> as Future>::Output>>,
+}
+
+impl Connection {
+    /// Create a [`Connection`] from a [`quinn::NewConnection`]
+    pub fn new(conn: quinn::Connection) -> Self {
+        Self {
+            conn: conn.clone(),
+            incoming_bi: Box::pin(stream::unfold(conn.clone(), |conn| async {
+                Some((conn.accept_bi().await, conn))
+            })),
+            opening_bi: None,
+            incoming_uni: Box::pin(stream::unfold(conn, |conn| async {
+                Some((conn.accept_uni().await, conn))
+            })),
+            opening_uni: None,
+        }
+    }
+}
+
+/// The error type for [`Connection`]
+///
+/// Wraps reasons a Quinn connection might be lost.
+#[derive(Debug)]
+pub struct ConnectionError(quinn::ConnectionError);
+
+impl std::error::Error for ConnectionError {}
+
+impl fmt::Display for ConnectionError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        self.0.fmt(f)
+    }
+}
+
+impl Error for ConnectionError {
+    fn is_timeout(&self) -> bool {
+        matches!(self.0, quinn::ConnectionError::TimedOut)
+    }
+
+    fn err_code(&self) -> Option<u64> {
+        match self.0 {
+            quinn::ConnectionError::ApplicationClosed(quinn_proto::ApplicationClose {
+                error_code,
+                ..
+            }) => Some(error_code.into_inner()),
+            _ => None,
+        }
+    }
+}
+
+impl From<quinn::ConnectionError> for ConnectionError {
+    fn from(e: quinn::ConnectionError) -> Self {
+        Self(e)
+    }
+}
+
+impl<B> quic::Connection<B> for Connection
+where
+    B: Buf,
+{
+    type SendStream = SendStream<B>;
+    type RecvStream = RecvStream;
+    type BidiStream = BidiStream<B>;
+    type OpenStreams = OpenStreams;
+    type Error = ConnectionError;
+
+    fn poll_accept_bidi(
+        &mut self,
+        cx: &mut task::Context<'_>,
+    ) -> Poll<Result<Option<Self::BidiStream>, Self::Error>> {
+        let (send, recv) = match ready!(self.incoming_bi.poll_next_unpin(cx)) {
+            Some(x) => x?,
+            None => return Poll::Ready(Ok(None)),
+        };
+        Poll::Ready(Ok(Some(Self::BidiStream {
+            send: Self::SendStream::new(send),
+            recv: Self::RecvStream::new(recv),
+        })))
+    }
+
+    fn poll_accept_recv(
+        &mut self,
+        cx: &mut task::Context<'_>,
+    ) -> Poll<Result<Option<Self::RecvStream>, Self::Error>> {
+        let recv = match ready!(self.incoming_uni.poll_next_unpin(cx)) {
+            Some(x) => x?,
+            None => return Poll::Ready(Ok(None)),
+        };
+        Poll::Ready(Ok(Some(Self::RecvStream::new(recv))))
+    }
+
+    fn poll_open_bidi(
+        &mut self,
+        cx: &mut task::Context<'_>,
+    ) -> Poll<Result<Self::BidiStream, Self::Error>> {
+        if self.opening_bi.is_none() {
+            self.opening_bi = Some(Box::pin(stream::unfold(self.conn.clone(), |conn| async {
+                Some((conn.clone().open_bi().await, conn))
+            })));
+        }
+
+        let (send, recv) =
+            ready!(self.opening_bi.as_mut().unwrap().poll_next_unpin(cx)).unwrap()?;
+        Poll::Ready(Ok(Self::BidiStream {
+            send: Self::SendStream::new(send),
+            recv: Self::RecvStream::new(recv),
+        }))
+    }
+
+    fn poll_open_send(
+        &mut self,
+        cx: &mut task::Context<'_>,
+    ) -> Poll<Result<Self::SendStream, Self::Error>> {
+        if self.opening_uni.is_none() {
+            self.opening_uni = Some(Box::pin(stream::unfold(self.conn.clone(), |conn| async {
+                Some((conn.open_uni().await, conn))
+            })));
+        }
+
+        let send = ready!(self.opening_uni.as_mut().unwrap().poll_next_unpin(cx)).unwrap()?;
+        Poll::Ready(Ok(Self::SendStream::new(send)))
+    }
+
+    fn opener(&self) -> Self::OpenStreams {
+        OpenStreams {
+            conn: self.conn.clone(),
+            opening_bi: None,
+            opening_uni: None,
+        }
+    }
+
+    fn close(&mut self, code: h3::error::Code, reason: &[u8]) {
+        self.conn.close(
+            VarInt::from_u64(code.value()).expect("error code VarInt"),
+            reason,
+        );
+    }
+}
+
+/// Stream opener backed by a Quinn connection
+///
+/// Implements [`quic::OpenStreams`] using [`quinn::Connection`],
+/// [`quinn::OpenBi`], [`quinn::OpenUni`].
+pub struct OpenStreams {
+    conn: quinn::Connection,
+    opening_bi: Option<BoxStream<'static, <OpenBi<'static> as Future>::Output>>,
+    opening_uni: Option<BoxStream<'static, <OpenUni<'static> as Future>::Output>>,
+}
+
+impl<B> quic::OpenStreams<B> for OpenStreams
+where
+    B: Buf,
+{
+    type RecvStream = RecvStream;
+    type SendStream = SendStream<B>;
+    type BidiStream = BidiStream<B>;
+    type Error = ConnectionError;
+
+    fn poll_open_bidi(
+        &mut self,
+        cx: &mut task::Context<'_>,
+    ) -> Poll<Result<Self::BidiStream, Self::Error>> {
+        if self.opening_bi.is_none() {
+            self.opening_bi = Some(Box::pin(stream::unfold(self.conn.clone(), |conn| async {
+                Some((conn.open_bi().await, conn))
+            })));
+        }
+
+        let (send, recv) =
+            ready!(self.opening_bi.as_mut().unwrap().poll_next_unpin(cx)).unwrap()?;
+        Poll::Ready(Ok(Self::BidiStream {
+            send: Self::SendStream::new(send),
+            recv: Self::RecvStream::new(recv),
+        }))
+    }
+
+    fn poll_open_send(
+        &mut self,
+        cx: &mut task::Context<'_>,
+    ) -> Poll<Result<Self::SendStream, Self::Error>> {
+        if self.opening_uni.is_none() {
+            self.opening_uni = Some(Box::pin(stream::unfold(self.conn.clone(), |conn| async {
+                Some((conn.open_uni().await, conn))
+            })));
+        }
+
+        let send = ready!(self.opening_uni.as_mut().unwrap().poll_next_unpin(cx)).unwrap()?;
+        Poll::Ready(Ok(Self::SendStream::new(send)))
+    }
+
+    fn close(&mut self, code: h3::error::Code, reason: &[u8]) {
+        self.conn.close(
+            VarInt::from_u64(code.value()).expect("error code VarInt"),
+            reason,
+        );
+    }
+}
+
+impl Clone for OpenStreams {
+    fn clone(&self) -> Self {
+        Self {
+            conn: self.conn.clone(),
+            opening_bi: None,
+            opening_uni: None,
+        }
+    }
+}
+
+/// Quinn-backed bidirectional stream
+///
+/// Implements [`quic::BidiStream`] which allows the stream to be split
+/// into two structs each implementing one direction.
+pub struct BidiStream<B>
+where
+    B: Buf,
+{
+    send: SendStream<B>,
+    recv: RecvStream,
+}
+
+impl<B> quic::BidiStream<B> for BidiStream<B>
+where
+    B: Buf,
+{
+    type SendStream = SendStream<B>;
+    type RecvStream = RecvStream;
+
+    fn split(self) -> (Self::SendStream, Self::RecvStream) {
+        (self.send, self.recv)
+    }
+}
+
+impl<B> quic::RecvStream for BidiStream<B>
+where
+    B: Buf,
+{
+    type Buf = Bytes;
+    type Error = ReadError;
+
+    fn poll_data(
+        &mut self,
+        cx: &mut task::Context<'_>,
+    ) -> Poll<Result<Option<Self::Buf>, Self::Error>> {
+        self.recv.poll_data(cx)
+    }
+
+    fn stop_sending(&mut self, error_code: u64) {
+        self.recv.stop_sending(error_code)
+    }
+}
+
+impl<B> quic::SendStream<B> for BidiStream<B>
+where
+    B: Buf,
+{
+    type Error = SendStreamError;
+
+    fn poll_ready(&mut self, cx: &mut task::Context<'_>) -> Poll<Result<(), Self::Error>> {
+        self.send.poll_ready(cx)
+    }
+
+    fn poll_finish(&mut self, cx: &mut task::Context<'_>) -> Poll<Result<(), Self::Error>> {
+        self.send.poll_finish(cx)
+    }
+
+    fn reset(&mut self, reset_code: u64) {
+        self.send.reset(reset_code)
+    }
+
+    fn send_data<D: Into<WriteBuf<B>>>(&mut self, data: D) -> Result<(), Self::Error> {
+        self.send.send_data(data)
+    }
+
+    fn id(&self) -> StreamId {
+        self.send.id()
+    }
+}
+
+/// Quinn-backed receive stream
+///
+/// Implements a [`quic::RecvStream`] backed by a [`quinn::RecvStream`].
+pub struct RecvStream {
+    stream: Option<quinn::RecvStream>,
+    read_chunk_fut: ReadChunkFuture,
+}
+
+type ReadChunkFuture = ReusableBoxFuture<
+    'static,
+    (
+        quinn::RecvStream,
+        Result<Option<quinn::Chunk>, quinn::ReadError>,
+    ),
+>;
+
+impl RecvStream {
+    fn new(stream: quinn::RecvStream) -> Self {
+        Self {
+            stream: Some(stream),
+            // Should only allocate once the first time it's used
+            read_chunk_fut: ReusableBoxFuture::new(async { unreachable!() }),
+        }
+    }
+}
+
+impl quic::RecvStream for RecvStream {
+    type Buf = Bytes;
+    type Error = ReadError;
+
+    fn poll_data(
+        &mut self,
+        cx: &mut task::Context<'_>,
+    ) -> Poll<Result<Option<Self::Buf>, Self::Error>> {
+        if let Some(mut stream) = self.stream.take() {
+            self.read_chunk_fut.set(async move {
+                let chunk = stream.read_chunk(usize::MAX, true).await;
+                (stream, chunk)
+            })
+        };
+
+        let (stream, chunk) = ready!(self.read_chunk_fut.poll(cx));
+        self.stream = Some(stream);
+        Poll::Ready(Ok(chunk?.map(|c| c.bytes)))
+    }
+
+    fn stop_sending(&mut self, error_code: u64) {
+        self.stream
+            .as_mut()
+            .unwrap()
+            .stop(VarInt::from_u64(error_code).expect("invalid error_code"))
+            .ok();
+    }
+}
+
+/// The error type for [`RecvStream`]
+///
+/// Wraps errors that occur when reading from a receive stream.
+#[derive(Debug)]
+pub struct ReadError(quinn::ReadError);
+
+impl std::error::Error for ReadError {}
+
+impl fmt::Display for ReadError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        self.0.fmt(f)
+    }
+}
+
+impl From<ReadError> for Arc<dyn Error> {
+    fn from(e: ReadError) -> Self {
+        Arc::new(e)
+    }
+}
+
+impl From<quinn::ReadError> for ReadError {
+    fn from(e: quinn::ReadError) -> Self {
+        Self(e)
+    }
+}
+
+impl Error for ReadError {
+    fn is_timeout(&self) -> bool {
+        matches!(
+            self.0,
+            quinn::ReadError::ConnectionLost(quinn::ConnectionError::TimedOut)
+        )
+    }
+
+    fn err_code(&self) -> Option<u64> {
+        match self.0 {
+            quinn::ReadError::ConnectionLost(quinn::ConnectionError::ApplicationClosed(
+                quinn_proto::ApplicationClose { error_code, .. },
+            )) => Some(error_code.into_inner()),
+            quinn::ReadError::Reset(error_code) => Some(error_code.into_inner()),
+            _ => None,
+        }
+    }
+}
+
+/// Quinn-backed send stream
+///
+/// Implements a [`quic::SendStream`] backed by a [`quinn::SendStream`].
+pub struct SendStream<B: Buf> {
+    stream: Option<quinn::SendStream>,
+    writing: Option<WriteBuf<B>>,
+    write_fut: WriteFuture,
+}
+
+type WriteFuture =
+    ReusableBoxFuture<'static, (quinn::SendStream, Result<usize, quinn::WriteError>)>;
+
+impl<B> SendStream<B>
+where
+    B: Buf,
+{
+    fn new(stream: quinn::SendStream) -> SendStream<B> {
+        Self {
+            stream: Some(stream),
+            writing: None,
+            write_fut: ReusableBoxFuture::new(async { unreachable!() }),
+        }
+    }
+}
+
+impl<B> quic::SendStream<B> for SendStream<B>
+where
+    B: Buf,
+{
+    type Error = SendStreamError;
+
+    fn poll_ready(&mut self, cx: &mut task::Context<'_>) -> Poll<Result<(), Self::Error>> {
+        if let Some(ref mut data) = self.writing {
+            while data.has_remaining() {
+                if let Some(mut stream) = self.stream.take() {
+                    let chunk = data.chunk().to_owned(); // FIXME - avoid copy
+                    self.write_fut.set(async move {
+                        let ret = stream.write(&chunk).await;
+                        (stream, ret)
+                    });
+                }
+
+                let (stream, res) = ready!(self.write_fut.poll(cx));
+                self.stream = Some(stream);
+                match res {
+                    Ok(cnt) => data.advance(cnt),
+                    Err(err) => {
+                        return Poll::Ready(Err(SendStreamError::Write(err)));
+                    }
+                }
+            }
+        }
+        self.writing = None;
+        Poll::Ready(Ok(()))
+    }
+
+    fn poll_finish(&mut self, cx: &mut task::Context<'_>) -> Poll<Result<(), Self::Error>> {
+        self.stream
+            .as_mut()
+            .unwrap()
+            .poll_finish(cx)
+            .map_err(Into::into)
+    }
+
+    fn reset(&mut self, reset_code: u64) {
+        let _ = self
+            .stream
+            .as_mut()
+            .unwrap()
+            .reset(VarInt::from_u64(reset_code).unwrap_or(VarInt::MAX));
+    }
+
+    fn send_data<D: Into<WriteBuf<B>>>(&mut self, data: D) -> Result<(), Self::Error> {
+        if self.writing.is_some() {
+            return Err(Self::Error::NotReady);
+        }
+        self.writing = Some(data.into());
+        Ok(())
+    }
+
+    fn id(&self) -> StreamId {
+        self.stream
+            .as_ref()
+            .unwrap()
+            .id()
+            .0
+            .try_into()
+            .expect("invalid stream id")
+    }
+}
+
+/// The error type for [`SendStream`]
+///
+/// Wraps errors that can happen writing to or polling a send stream.
+#[derive(Debug)]
+pub enum SendStreamError {
+    /// Errors when writing, wrapping a [`quinn::WriteError`]
+    Write(WriteError),
+    /// Error when the stream is not ready, because it is still sending
+    /// data from a previous call
+    NotReady,
+}
+
+impl std::error::Error for SendStreamError {}
+
+impl Display for SendStreamError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{:?}", self)
+    }
+}
+
+impl From<WriteError> for SendStreamError {
+    fn from(e: WriteError) -> Self {
+        Self::Write(e)
+    }
+}
+
+impl Error for SendStreamError {
+    fn is_timeout(&self) -> bool {
+        matches!(
+            self,
+            Self::Write(quinn::WriteError::ConnectionLost(
+                quinn::ConnectionError::TimedOut
+            ))
+        )
+    }
+
+    fn err_code(&self) -> Option<u64> {
+        match self {
+            Self::Write(quinn::WriteError::Stopped(error_code)) => Some(error_code.into_inner()),
+            Self::Write(quinn::WriteError::ConnectionLost(
+                quinn::ConnectionError::ApplicationClosed(quinn_proto::ApplicationClose {
+                    error_code,
+                    ..
+                }),
+            )) => Some(error_code.into_inner()),
+            _ => None,
+        }
+    }
+}
+
+impl From<SendStreamError> for Arc<dyn Error> {
+    fn from(e: SendStreamError) -> Self {
+        Arc::new(e)
+    }
+}
diff --git a/quinn b/quinn
new file mode 160000
index 0000000..b56d60b
--- /dev/null
+++ b/quinn
@@ -0,0 +1 @@
+Subproject commit b56d60bbec577d73e67abbba60ed389f0589f208
diff --git a/src/backend/mod.rs b/src/backend/mod.rs
index 6a92ec8..b502369 100644
--- a/src/backend/mod.rs
+++ b/src/backend/mod.rs
@@ -168,7 +168,8 @@ impl Backend {
     let owned_trust_anchors: Vec<_> = certs
       .iter()
       .map(|v| {
-        let trust_anchor = tokio_rustls::webpki::TrustAnchor::try_from_cert_der(&v.0).unwrap();
+        // let trust_anchor = tokio_rustls::webpki::TrustAnchor::try_from_cert_der(&v.0).unwrap();
+        let trust_anchor = webpki::TrustAnchor::try_from_cert_der(&v.0).unwrap();
         rustls::OwnedTrustAnchor::from_subject_spki_name_constraints(
           trust_anchor.subject,
           trust_anchor.spki,
@@ -279,7 +280,7 @@ impl Backends {
               let client_certs_verifier = rustls::server::AllowAnyAuthenticatedClient::new(client_ca_roots_local);
               ServerConfig::builder()
                 .with_safe_defaults()
-                .with_client_cert_verifier(client_certs_verifier)
+                .with_client_cert_verifier(Arc::new(client_certs_verifier))
                 .with_cert_resolver(Arc::new(resolver_local))
             };
             server_config_local.alpn_protocols.push(b"h2".to_vec());