diff --git a/cmd/gost/cfg.go b/cmd/gost/cfg.go
index dc696c8..dddbdf9 100644
--- a/cmd/gost/cfg.go
+++ b/cmd/gost/cfg.go
@@ -6,7 +6,6 @@ import (
 	"crypto/x509"
 	"encoding/json"
 	"errors"
-	"io/ioutil"
 	"net"
 	"net/url"
 	"os"
@@ -71,7 +70,7 @@ func loadCA(caFile string) (cp *x509.CertPool, err error) {
 		return
 	}
 	cp = x509.NewCertPool()
-	data, err := ioutil.ReadFile(caFile)
+	data, err := os.ReadFile(caFile)
 	if err != nil {
 		return nil, err
 	}
diff --git a/cmd/gost/peer.go b/cmd/gost/peer.go
index 9e1d00f..6f5b32c 100644
--- a/cmd/gost/peer.go
+++ b/cmd/gost/peer.go
@@ -5,7 +5,6 @@ import (
 	"bytes"
 	"encoding/json"
 	"io"
-	"io/ioutil"
 	"strconv"
 	"strings"
 	"time"
@@ -83,7 +82,7 @@ func (cfg *peerConfig) Reload(r io.Reader) error {
 }
 
 func (cfg *peerConfig) parse(r io.Reader) error {
-	data, err := ioutil.ReadAll(r)
+	data, err := io.ReadAll(r)
 	if err != nil {
 		return err
 	}
diff --git a/common_test.go b/common_test.go
index 9e030d6..28bcf7c 100644
--- a/common_test.go
+++ b/common_test.go
@@ -7,7 +7,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net"
 	"net/http"
 	"net/url"
@@ -36,7 +35,7 @@ func init() {
 
 var (
 	httpTestHandler = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		data, _ := ioutil.ReadAll(r.Body)
+		data, _ := io.ReadAll(r.Body)
 		if len(data) == 0 {
 			data = []byte("Hello World!")
 		}
@@ -87,7 +86,7 @@ func httpRoundtrip(conn net.Conn, targetURL string, data []byte) (err error) {
 		return errors.New(resp.Status)
 	}
 
-	recv, err := ioutil.ReadAll(resp.Body)
+	recv, err := io.ReadAll(resp.Body)
 	if err != nil {
 		return
 	}
diff --git a/dns.go b/dns.go
index 1b02404..cc67718 100644
--- a/dns.go
+++ b/dns.go
@@ -7,7 +7,6 @@ import (
 	"encoding/base64"
 	"errors"
 	"io"
-	"io/ioutil"
 	"net"
 	"net/http"
 	"strconv"
@@ -267,7 +266,7 @@ func (l *dnsListener) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 			return
 		}
 
-		buf, err = ioutil.ReadAll(r.Body)
+		buf, err = io.ReadAll(r.Body)
 		if err != nil {
 			http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError)
 			return
diff --git a/http2.go b/http2.go
index 6587f03..de152ea 100644
--- a/http2.go
+++ b/http2.go
@@ -9,7 +9,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net"
 	"net/http"
 	"net/http/httputil"
@@ -389,7 +388,7 @@ func (h *http2Handler) roundTrip(w http.ResponseWriter, r *http.Request) {
 		ProtoMajor: 2,
 		ProtoMinor: 0,
 		Header:     http.Header{},
-		Body:       ioutil.NopCloser(bytes.NewReader([]byte{})),
+		Body:       io.NopCloser(bytes.NewReader([]byte{})),
 	}
 
 	if !h.authenticate(w, r, resp) {
diff --git a/http2_test.go b/http2_test.go
index 762c6df..c769d7a 100644
--- a/http2_test.go
+++ b/http2_test.go
@@ -5,7 +5,7 @@ import (
 	"crypto/rand"
 	"crypto/tls"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net"
 	"net/http"
 	"net/http/httptest"
@@ -997,7 +997,7 @@ func TestHTTP2ProxyWithWebProbeResist(t *testing.T) {
 	if err != nil {
 		t.Error(err)
 	}
-	recv, _ := ioutil.ReadAll(conn)
+	recv, _ := io.ReadAll(conn)
 	if !bytes.Equal(recv, []byte("Hello World!")) {
 		t.Error("data not equal")
 	}
@@ -1053,7 +1053,7 @@ func TestHTTP2ProxyWithHostProbeResist(t *testing.T) {
 		Proto:         "HTTP/2.0",
 		ProtoMajor:    2,
 		ProtoMinor:    0,
-		Body:          ioutil.NopCloser(bytes.NewReader(sendData)),
+		Body:          io.NopCloser(bytes.NewReader(sendData)),
 		Host:          "github.com:443",
 		ContentLength: int64(len(sendData)),
 	}
@@ -1068,7 +1068,7 @@ func TestHTTP2ProxyWithHostProbeResist(t *testing.T) {
 		t.Error("got non-200 status:", resp.Status)
 	}
 
-	recv, _ := ioutil.ReadAll(resp.Body)
+	recv, _ := io.ReadAll(resp.Body)
 	if !bytes.Equal(sendData, recv) {
 		t.Error("data not equal")
 	}
@@ -1105,7 +1105,7 @@ func TestHTTP2ProxyWithFileProbeResist(t *testing.T) {
 	if err != nil {
 		t.Error(err)
 	}
-	recv, _ := ioutil.ReadAll(conn)
+	recv, _ := io.ReadAll(conn)
 	if !bytes.Equal(recv, []byte("Hello World!")) {
 		t.Error("data not equal")
 	}
diff --git a/http_test.go b/http_test.go
index a4f1041..dcc2e05 100644
--- a/http_test.go
+++ b/http_test.go
@@ -4,7 +4,7 @@ import (
 	"bytes"
 	"crypto/rand"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net"
 	"net/http"
 	"net/http/httptest"
@@ -249,7 +249,7 @@ func TestHTTPProxyWithWebProbeResist(t *testing.T) {
 		t.Error("got status:", resp.Status)
 	}
 
-	recv, _ := ioutil.ReadAll(resp.Body)
+	recv, _ := io.ReadAll(resp.Body)
 	if !bytes.Equal(recv, []byte("Hello World!")) {
 		t.Error("data not equal")
 	}
@@ -296,7 +296,7 @@ func TestHTTPProxyWithHostProbeResist(t *testing.T) {
 		t.Error("got status:", resp.Status)
 	}
 
-	recv, _ := ioutil.ReadAll(resp.Body)
+	recv, _ := io.ReadAll(resp.Body)
 	if !bytes.Equal(sendData, recv) {
 		t.Error("data not equal")
 	}
@@ -332,7 +332,7 @@ func TestHTTPProxyWithFileProbeResist(t *testing.T) {
 		t.Error("got status:", resp.Status)
 	}
 
-	recv, _ := ioutil.ReadAll(resp.Body)
+	recv, _ := io.ReadAll(resp.Body)
 	if !bytes.Equal(recv, []byte("Hello World!")) {
 		t.Error("data not equal, got:", string(recv))
 	}
diff --git a/resolver.go b/resolver.go
index 69e659d..0f07ceb 100644
--- a/resolver.go
+++ b/resolver.go
@@ -8,7 +8,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net"
 	"net/http"
 	"net/url"
@@ -915,7 +914,7 @@ func (ex *dohExchanger) Exchange(ctx context.Context, query []byte) ([]byte, err
 	}
 
 	// Read wireformat response from the body
-	buf, err := ioutil.ReadAll(resp.Body)
+	buf, err := io.ReadAll(resp.Body)
 	if err != nil {
 		return nil, fmt.Errorf("failed to read the response body: %s", err)
 	}
diff --git a/sni_test.go b/sni_test.go
index 0bfa994..18cecbc 100644
--- a/sni_test.go
+++ b/sni_test.go
@@ -7,7 +7,7 @@ import (
 	"crypto/tls"
 	"errors"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"net/http/httptest"
 	"net/url"
@@ -69,7 +69,7 @@ func sniRoundtrip(client *Client, server *Server, targetURL string, data []byte)
 		return errors.New(resp.Status)
 	}
 
-	recv, err := ioutil.ReadAll(resp.Body)
+	recv, err := io.ReadAll(resp.Body)
 	if err != nil {
 		return
 	}
diff --git a/ssh.go b/ssh.go
index f772503..17ad653 100644
--- a/ssh.go
+++ b/ssh.go
@@ -6,7 +6,7 @@ import (
 	"encoding/binary"
 	"errors"
 	"fmt"
-	"io/ioutil"
+	"os"
 	"net"
 	"strconv"
 	"strings"
@@ -33,7 +33,7 @@ var (
 
 // ParseSSHKeyFile parses ssh key file.
 func ParseSSHKeyFile(fp string) (ssh.Signer, error) {
-	key, err := ioutil.ReadFile(fp)
+	key, err := os.ReadFile(fp)
 	if err != nil {
 		return nil, err
 	}
@@ -42,7 +42,7 @@ func ParseSSHKeyFile(fp string) (ssh.Signer, error) {
 
 // ParseSSHAuthorizedKeysFile parses ssh Authorized Keys file.
 func ParseSSHAuthorizedKeysFile(fp string) (map[string]bool, error) {
-	authorizedKeysBytes, err := ioutil.ReadFile(fp)
+	authorizedKeysBytes, err := os.ReadFile(fp)
 	if err != nil {
 		return nil, err
 	}