diff --git a/pkg/message/message.go b/pkg/message/message.go
index bb64e99..24bf39c 100644
--- a/pkg/message/message.go
+++ b/pkg/message/message.go
@@ -3,7 +3,6 @@ package message
 
 import (
 	"io"
-	"io/ioutil"
 	"net/mail"
 	"net/textproto"
 	"time"
@@ -97,7 +96,7 @@ func (d *Delivery) Size() int64 {
 
 // Source contains the raw content of the message.
 func (d *Delivery) Source() (io.ReadCloser, error) {
-	return ioutil.NopCloser(d.Reader), nil
+	return io.NopCloser(d.Reader), nil
 }
 
 // Seen getter.
diff --git a/pkg/rest/client/rest_test.go b/pkg/rest/client/rest_test.go
index c4d8f6e..175dbc6 100644
--- a/pkg/rest/client/rest_test.go
+++ b/pkg/rest/client/rest_test.go
@@ -2,7 +2,7 @@ package client
 
 import (
 	"bytes"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"net/url"
 	"testing"
@@ -33,7 +33,7 @@ func (m *mockHTTPClient) Do(req *http.Request) (resp *http.Response, err error)
 	}
 	resp = &http.Response{
 		StatusCode: m.statusCode,
-		Body:       ioutil.NopCloser(bytes.NewBufferString(m.body)),
+		Body:       io.NopCloser(bytes.NewBufferString(m.body)),
 	}
 	return
 }
@@ -43,7 +43,7 @@ func (m *mockHTTPClient) ReqBody() []byte {
 	if err != nil {
 		return nil
 	}
-	body, err := ioutil.ReadAll(r)
+	body, err := io.ReadAll(r)
 	if err != nil {
 		return nil
 	}
diff --git a/pkg/storage/file/fstore_test.go b/pkg/storage/file/fstore_test.go
index bd325cd..d83a874 100644
--- a/pkg/storage/file/fstore_test.go
+++ b/pkg/storage/file/fstore_test.go
@@ -4,7 +4,6 @@ import (
 	"bytes"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"log"
 	"net/mail"
 	"os"
@@ -192,7 +191,7 @@ func TestGetLatestMessage(t *testing.T) {
 
 // setupDataStore creates a new FileDataStore in a temporary directory
 func setupDataStore(cfg config.Storage, extHost *extension.Host) (*Store, *bytes.Buffer) {
-	path, err := ioutil.TempDir("", "inbucket")
+	path, err := os.MkdirTemp("", "inbucket")
 	if err != nil {
 		panic(err)
 	}
@@ -228,7 +227,7 @@ func deliverMessage(ds *Store, mbName string, subject string, date time.Time) (s
 		meta.To[0].Address, meta.From.Address, subject)
 	delivery := &message.Delivery{
 		Meta:   meta,
-		Reader: ioutil.NopCloser(strings.NewReader(testMsg)),
+		Reader: io.NopCloser(strings.NewReader(testMsg)),
 	}
 	id, err := ds.AddMessage(delivery)
 	if err != nil {
diff --git a/pkg/storage/mem/message.go b/pkg/storage/mem/message.go
index 3c14898..2fee702 100644
--- a/pkg/storage/mem/message.go
+++ b/pkg/storage/mem/message.go
@@ -4,7 +4,6 @@ import (
 	"bytes"
 	"container/list"
 	"io"
-	"io/ioutil"
 	"net/mail"
 	"time"
 
@@ -47,7 +46,7 @@ func (m *Message) Subject() string { return m.subject }
 
 // Source returns a reader for the message source.
 func (m *Message) Source() (io.ReadCloser, error) {
-	return ioutil.NopCloser(bytes.NewReader(m.source)), nil
+	return io.NopCloser(bytes.NewReader(m.source)), nil
 }
 
 // Size returns the message size in bytes.
diff --git a/pkg/storage/mem/store.go b/pkg/storage/mem/store.go
index 7c1a78e..c25b30e 100644
--- a/pkg/storage/mem/store.go
+++ b/pkg/storage/mem/store.go
@@ -2,7 +2,7 @@ package mem
 
 import (
 	"fmt"
-	"io/ioutil"
+	"io"
 	"sort"
 	"strconv"
 	"sync"
@@ -62,7 +62,7 @@ func (s *Store) AddMessage(message storage.Message) (id string, err error) {
 		err = ierr
 		return
 	}
-	source, ierr := ioutil.ReadAll(r)
+	source, ierr := io.ReadAll(r)
 	if ierr != nil {
 		err = ierr
 		return
diff --git a/pkg/test/integration_test.go b/pkg/test/integration_test.go
index 60d29bc..fc91c5d 100644
--- a/pkg/test/integration_test.go
+++ b/pkg/test/integration_test.go
@@ -4,7 +4,7 @@ import (
 	"bytes"
 	"context"
 	"fmt"
-	"io/ioutil"
+	"io"
 	smtpclient "net/smtp"
 	"os"
 	"path/filepath"
@@ -266,7 +266,7 @@ func readTestData(path ...string) []byte {
 	if err != nil {
 		panic(err)
 	}
-	data, err := ioutil.ReadAll(f)
+	data, err := io.ReadAll(f)
 	if err != nil {
 		panic(err)
 	}
diff --git a/pkg/test/storage_suite.go b/pkg/test/storage_suite.go
index f8a7ca9..c4b4d9d 100644
--- a/pkg/test/storage_suite.go
+++ b/pkg/test/storage_suite.go
@@ -3,7 +3,7 @@ package test
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net/mail"
 	"strings"
 	"testing"
@@ -159,7 +159,7 @@ func testContent(t *testing.T, store storage.Store, extHost *extension.Host) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	got, err := ioutil.ReadAll(r)
+	got, err := io.ReadAll(r)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -455,7 +455,7 @@ func DeliverToStore(
 		meta.To[0].Address, meta.From.Address, subject)
 	delivery := &message.Delivery{
 		Meta:   meta,
-		Reader: ioutil.NopCloser(strings.NewReader(testMsg)),
+		Reader: io.NopCloser(strings.NewReader(testMsg)),
 	}
 	id, err := store.AddMessage(delivery)
 	if err != nil {
diff --git a/pkg/webui/root_controller.go b/pkg/webui/root_controller.go
index 9338990..3f05ec8 100644
--- a/pkg/webui/root_controller.go
+++ b/pkg/webui/root_controller.go
@@ -2,7 +2,7 @@ package webui
 
 import (
 	"fmt"
-	"io/ioutil"
+	"os"
 	"net/http"
 
 	"github.com/inbucket/inbucket/pkg/config"
@@ -11,7 +11,7 @@ import (
 
 // RootGreeting serves the Inbucket greeting.
 func RootGreeting(w http.ResponseWriter, req *http.Request, ctx *web.Context) (err error) {
-	greeting, err := ioutil.ReadFile(ctx.RootConfig.Web.GreetingFile)
+	greeting, err := os.ReadFile(ctx.RootConfig.Web.GreetingFile)
 	if err != nil {
 		return fmt.Errorf("Failed to load greeting: %v", err)
 	}