diff --git a/.circleci/config.yml b/.circleci/config.yml
index ecb33f6..ebd12c1 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -67,4 +67,4 @@ workflows:
       - test:
           matrix:
             parameters:
-              version: ["1.18", "1.17", "1.16"]
+              version: ["1.22", "1.21", "1.20"]
diff --git a/client.go b/client.go
index 04fdafe..170301d 100644
--- a/client.go
+++ b/client.go
@@ -11,7 +11,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net"
 	"net/http"
 	"net/http/httptrace"
@@ -400,7 +399,7 @@ func (d *Dialer) DialContext(ctx context.Context, urlStr string, requestHeader h
 		// debugging.
 		buf := make([]byte, 1024)
 		n, _ := io.ReadFull(resp.Body, buf)
-		resp.Body = ioutil.NopCloser(bytes.NewReader(buf[:n]))
+		resp.Body = io.NopCloser(bytes.NewReader(buf[:n]))
 		return nil, resp, ErrBadHandshake
 	}
 
@@ -418,7 +417,7 @@ func (d *Dialer) DialContext(ctx context.Context, urlStr string, requestHeader h
 		break
 	}
 
-	resp.Body = ioutil.NopCloser(bytes.NewReader([]byte{}))
+	resp.Body = io.NopCloser(bytes.NewReader([]byte{}))
 	conn.subprotocol = resp.Header.Get("Sec-Websocket-Protocol")
 
 	netConn.SetDeadline(time.Time{})
diff --git a/client_server_test.go b/client_server_test.go
index a47df48..610fbe2 100644
--- a/client_server_test.go
+++ b/client_server_test.go
@@ -14,7 +14,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"log"
 	"net"
 	"net/http"
@@ -24,6 +23,7 @@ import (
 	"net/url"
 	"reflect"
 	"strings"
+	"sync"
 	"testing"
 	"time"
 )
@@ -45,12 +45,15 @@ var cstDialer = Dialer{
 	HandshakeTimeout: 30 * time.Second,
 }
 
-type cstHandler struct{ *testing.T }
+type cstHandler struct {
+	*testing.T
+	s *cstServer
+}
 
 type cstServer struct {
-	*httptest.Server
-	URL string
-	t   *testing.T
+	URL    string
+	Server *httptest.Server
+	wg     sync.WaitGroup
 }
 
 const (
@@ -59,9 +62,15 @@ const (
 	cstRequestURI = cstPath + "?" + cstRawQuery
 )
 
+func (s *cstServer) Close() {
+	s.Server.Close()
+	// Wait for handler functions to complete.
+	s.wg.Wait()
+}
+
 func newServer(t *testing.T) *cstServer {
 	var s cstServer
-	s.Server = httptest.NewServer(cstHandler{t})
+	s.Server = httptest.NewServer(cstHandler{T: t, s: &s})
 	s.Server.URL += cstRequestURI
 	s.URL = makeWsProto(s.Server.URL)
 	return &s
@@ -69,13 +78,19 @@ func newServer(t *testing.T) *cstServer {
 
 func newTLSServer(t *testing.T) *cstServer {
 	var s cstServer
-	s.Server = httptest.NewTLSServer(cstHandler{t})
+	s.Server = httptest.NewTLSServer(cstHandler{T: t, s: &s})
 	s.Server.URL += cstRequestURI
 	s.URL = makeWsProto(s.Server.URL)
 	return &s
 }
 
 func (t cstHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	// Because tests wait for a response from a server, we are guaranteed that
+	// the wait group count is incremented before the test waits on the group
+	// in the call to (*cstServer).Close().
+	t.s.wg.Add(1)
+	defer t.s.wg.Done()
+
 	if r.URL.Path != cstPath {
 		t.Logf("path=%v, want %v", r.URL.Path, cstPath)
 		http.Error(w, "bad path", http.StatusBadRequest)
@@ -549,7 +564,7 @@ func TestRespOnBadHandshake(t *testing.T) {
 		t.Errorf("resp.StatusCode=%d, want %d", resp.StatusCode, expectedStatus)
 	}
 
-	p, err := ioutil.ReadAll(resp.Body)
+	p, err := io.ReadAll(resp.Body)
 	if err != nil {
 		t.Fatalf("ReadFull(resp.Body) returned error %v", err)
 	}
diff --git a/compression_test.go b/compression_test.go
index 8a26b30..23591c4 100644
--- a/compression_test.go
+++ b/compression_test.go
@@ -4,7 +4,6 @@ import (
 	"bytes"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"testing"
 )
 
@@ -42,7 +41,7 @@ func textMessages(num int) [][]byte {
 }
 
 func BenchmarkWriteNoCompression(b *testing.B) {
-	w := ioutil.Discard
+	w := io.Discard
 	c := newTestConn(nil, w, false)
 	messages := textMessages(100)
 	b.ResetTimer()
@@ -53,7 +52,7 @@ func BenchmarkWriteNoCompression(b *testing.B) {
 }
 
 func BenchmarkWriteWithCompression(b *testing.B) {
-	w := ioutil.Discard
+	w := io.Discard
 	c := newTestConn(nil, w, false)
 	messages := textMessages(100)
 	c.enableWriteCompression = true
diff --git a/conn.go b/conn.go
index 5161ef8..9353252 100644
--- a/conn.go
+++ b/conn.go
@@ -9,7 +9,6 @@ import (
 	"encoding/binary"
 	"errors"
 	"io"
-	"io/ioutil"
 	"math/rand"
 	"net"
 	"strconv"
@@ -795,7 +794,7 @@ func (c *Conn) advanceFrame() (int, error) {
 	// 1. Skip remainder of previous frame.
 
 	if c.readRemaining > 0 {
-		if _, err := io.CopyN(ioutil.Discard, c.br, c.readRemaining); err != nil {
+		if _, err := io.CopyN(io.Discard, c.br, c.readRemaining); err != nil {
 			return noFrame, err
 		}
 	}
@@ -1094,7 +1093,7 @@ func (c *Conn) ReadMessage() (messageType int, p []byte, err error) {
 	if err != nil {
 		return messageType, nil, err
 	}
-	p, err = ioutil.ReadAll(r)
+	p, err = io.ReadAll(r)
 	return messageType, p, err
 }
 
diff --git a/conn_broadcast_test.go b/conn_broadcast_test.go
index 6e744fc..d8a6492 100644
--- a/conn_broadcast_test.go
+++ b/conn_broadcast_test.go
@@ -6,7 +6,6 @@ package websocket
 
 import (
 	"io"
-	"io/ioutil"
 	"sync/atomic"
 	"testing"
 )
@@ -45,7 +44,7 @@ func newBroadcastConn(c *Conn) *broadcastConn {
 
 func newBroadcastBench(usePrepared, compression bool) *broadcastBench {
 	bench := &broadcastBench{
-		w:           ioutil.Discard,
+		w:           io.Discard,
 		doneCh:      make(chan struct{}),
 		closeCh:     make(chan struct{}),
 		usePrepared: usePrepared,
diff --git a/conn_test.go b/conn_test.go
index 06e5184..e9f5441 100644
--- a/conn_test.go
+++ b/conn_test.go
@@ -10,7 +10,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net"
 	"reflect"
 	"sync"
@@ -125,7 +124,7 @@ func TestFraming(t *testing.T) {
 						}
 
 						t.Logf("frame size: %d", n)
-						rbuf, err := ioutil.ReadAll(r)
+						rbuf, err := io.ReadAll(r)
 						if err != nil {
 							t.Errorf("%s: ReadFull() returned rbuf, %v", name, err)
 							continue
@@ -367,7 +366,7 @@ func TestCloseFrameBeforeFinalMessageFrame(t *testing.T) {
 	if op != BinaryMessage || err != nil {
 		t.Fatalf("NextReader() returned %d, %v", op, err)
 	}
-	_, err = io.Copy(ioutil.Discard, r)
+	_, err = io.Copy(io.Discard, r)
 	if !reflect.DeepEqual(err, expectedErr) {
 		t.Fatalf("io.Copy() returned %v, want %v", err, expectedErr)
 	}
@@ -401,7 +400,7 @@ func TestEOFWithinFrame(t *testing.T) {
 		if op != BinaryMessage || err != nil {
 			t.Fatalf("%d: NextReader() returned %d, %v", n, op, err)
 		}
-		_, err = io.Copy(ioutil.Discard, r)
+		_, err = io.Copy(io.Discard, r)
 		if err != errUnexpectedEOF {
 			t.Fatalf("%d: io.Copy() returned %v, want %v", n, err, errUnexpectedEOF)
 		}
@@ -426,7 +425,7 @@ func TestEOFBeforeFinalFrame(t *testing.T) {
 	if op != BinaryMessage || err != nil {
 		t.Fatalf("NextReader() returned %d, %v", op, err)
 	}
-	_, err = io.Copy(ioutil.Discard, r)
+	_, err = io.Copy(io.Discard, r)
 	if err != errUnexpectedEOF {
 		t.Fatalf("io.Copy() returned %v, want %v", err, errUnexpectedEOF)
 	}
@@ -490,7 +489,7 @@ func TestReadLimit(t *testing.T) {
 		if op != BinaryMessage || err != nil {
 			t.Fatalf("2: NextReader() returned %d, %v", op, err)
 		}
-		_, err = io.Copy(ioutil.Discard, r)
+		_, err = io.Copy(io.Discard, r)
 		if err != ErrReadLimit {
 			t.Fatalf("io.Copy() returned %v", err)
 		}
diff --git a/examples/autobahn/server.go b/examples/autobahn/server.go
index 8b17fe3..2d6d36f 100644
--- a/examples/autobahn/server.go
+++ b/examples/autobahn/server.go
@@ -84,7 +84,7 @@ func echoCopyFull(w http.ResponseWriter, r *http.Request) {
 }
 
 // echoReadAll echoes messages from the client by reading the entire message
-// with ioutil.ReadAll.
+// with io.ReadAll.
 func echoReadAll(w http.ResponseWriter, r *http.Request, writeMessage, writePrepared bool) {
 	conn, err := upgrader.Upgrade(w, r, nil)
 	if err != nil {
diff --git a/examples/filewatch/main.go b/examples/filewatch/main.go
index d4bf80e..57d5a0b 100644
--- a/examples/filewatch/main.go
+++ b/examples/filewatch/main.go
@@ -7,7 +7,6 @@ package main
 import (
 	"flag"
 	"html/template"
-	"io/ioutil"
 	"log"
 	"net/http"
 	"os"
@@ -49,7 +48,7 @@ func readFileIfModified(lastMod time.Time) ([]byte, time.Time, error) {
 	if !fi.ModTime().After(lastMod) {
 		return nil, lastMod, nil
 	}
-	p, err := ioutil.ReadFile(filename)
+	p, err := os.ReadFile(filename)
 	if err != nil {
 		return nil, fi.ModTime(), err
 	}
diff --git a/go.mod b/go.mod
index 1a7afd5..dba1e22 100644
--- a/go.mod
+++ b/go.mod
@@ -1,3 +1,7 @@
 module github.com/gorilla/websocket
 
-go 1.12
+go 1.20
+
+retract (
+    v1.5.2 // tag accidentally overwritten
+)
diff --git a/server.go b/server.go
index e877920..ff7d03a 100644
--- a/server.go
+++ b/server.go
@@ -172,14 +172,10 @@ func (u *Upgrader) Upgrade(w http.ResponseWriter, r *http.Request, responseHeade
 		}
 	}
 
-	h, ok := w.(http.Hijacker)
-	if !ok {
-		return u.returnError(w, r, http.StatusInternalServerError, "websocket: response does not implement http.Hijacker")
-	}
-	var brw *bufio.ReadWriter
-	netConn, brw, err := h.Hijack()
+	netConn, brw, err := http.NewResponseController(w).Hijack()
 	if err != nil {
-		return u.returnError(w, r, http.StatusInternalServerError, err.Error())
+		return u.returnError(w, r, http.StatusInternalServerError,
+			"websocket: hijack: "+err.Error())
 	}
 
 	if brw.Reader.Buffered() > 0 {
diff --git a/server_test.go b/server_test.go
index 0c341ac..2db5e89 100644
--- a/server_test.go
+++ b/server_test.go
@@ -7,8 +7,10 @@ package websocket
 import (
 	"bufio"
 	"bytes"
+	"errors"
 	"net"
 	"net/http"
+	"net/http/httptest"
 	"reflect"
 	"strings"
 	"testing"
@@ -147,3 +149,23 @@ func TestBufioReuse(t *testing.T) {
 		}
 	}
 }
+
+func TestHijack_NotSupported(t *testing.T) {
+	t.Parallel()
+
+	req := httptest.NewRequest(http.MethodGet, "http://example.com", nil)
+	req.Header.Set("Upgrade", "websocket")
+	req.Header.Set("Connection", "upgrade")
+	req.Header.Set("Sec-Websocket-Key", "dGhlIHNhbXBsZSBub25jZQ==")
+	req.Header.Set("Sec-Websocket-Version", "13")
+
+	recorder := httptest.NewRecorder()
+
+	upgrader := Upgrader{}
+	_, err := upgrader.Upgrade(recorder, req, nil)
+
+	if want := (HandshakeError{}); !errors.As(err, &want) || recorder.Code != http.StatusInternalServerError {
+		t.Errorf("want %T and status_code=%d", want, http.StatusInternalServerError)
+		t.Fatalf("got err=%T and status_code=%d", err, recorder.Code)
+	}
+}