diff --git a/client_121_test.go b/client_121_test.go
new file mode 100644
index 0000000..84f091a
--- /dev/null
+++ b/client_121_test.go
@@ -0,0 +1,121 @@
+// SPDX-FileCopyrightText: 2024 The go-mail Authors
+//
+// SPDX-License-Identifier: MIT
+
+//go:build go1.21
+// +build go1.21
+
+package mail
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"os"
+	"reflect"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/wneessen/go-mail/log"
+)
+
+func TestNewClientNewVersionsOnly(t *testing.T) {
+	tests := []struct {
+		name       string
+		option     Option
+		expectFunc func(c *Client) error
+		shouldfail bool
+		expectErr  *error
+	}{
+		{
+			"WithLogger log.JSONlog", WithLogger(log.NewJSON(os.Stderr, log.LevelDebug)),
+			func(c *Client) error {
+				if c.logger == nil {
+					return errors.New("failed to set logger. Want logger bug got got nil")
+				}
+				loggerType := reflect.TypeOf(c.logger).String()
+				if loggerType != "*log.JSONlog" {
+					return fmt.Errorf("failed to set logger. Want logger type: %s, got: %s",
+						"*log.JSONlog", loggerType)
+				}
+				return nil
+			},
+			false, nil,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			client, err := NewClient(DefaultHost, tt.option)
+			if !tt.shouldfail && err != nil {
+				t.Fatalf("failed to create new client: %s", err)
+			}
+			if tt.shouldfail && err == nil {
+				t.Errorf("client creation was supposed to fail, but it didn't")
+			}
+			if tt.shouldfail && tt.expectErr != nil {
+				if !errors.Is(err, *tt.expectErr) {
+					t.Errorf("error for NewClient mismatch. Expected: %s, got: %s",
+						*tt.expectErr, err)
+				}
+			}
+			if tt.expectFunc != nil {
+				if err = tt.expectFunc(client); err != nil {
+					t.Errorf("NewClient with custom option failed: %s", err)
+				}
+			}
+		})
+	}
+}
+
+func TestClient_DialWithContextNewVersionsOnly(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+	PortAdder.Add(1)
+	serverPort := int(TestServerPortBase + PortAdder.Load())
+	featureSet := "250-AUTH PLAIN\r\n250-8BITMIME\r\n250-DSN\r\n250 SMTPUTF8"
+	go func() {
+		if err := simpleSMTPServer(ctx, t, &serverProps{FeatureSet: featureSet, ListenPort: serverPort}); err != nil {
+			t.Errorf("failed to start test server: %s", err)
+			return
+		}
+	}()
+	time.Sleep(time.Millisecond * 30)
+	t.Run("connect with full debug logging and auth logging", func(t *testing.T) {
+		ctxDial, cancelDial := context.WithTimeout(ctx, time.Millisecond*500)
+		t.Cleanup(cancelDial)
+
+		logBuffer := bytes.NewBuffer(nil)
+		client, err := NewClient(DefaultHost, WithPort(serverPort), WithTLSPolicy(NoTLS),
+			WithDebugLog(), WithLogAuthData(), WithLogger(log.NewJSON(logBuffer, log.LevelDebug)),
+			WithSMTPAuth(SMTPAuthPlain), WithUsername("test"), WithPassword("password"))
+		if err != nil {
+			t.Fatalf("failed to create new client: %s", err)
+		}
+
+		if err = client.DialWithContext(ctxDial); err != nil {
+			t.Fatalf("failed to connect to the test server: %s", err)
+		}
+		t.Cleanup(func() {
+			if err = client.Close(); err != nil {
+				t.Errorf("failed to close the client: %s", err)
+			}
+		})
+
+		logs := parseJSONLog(t, logBuffer)
+		if len(logs.Lines) == 0 {
+			t.Errorf("failed to enable debug logging, but no logs were found")
+		}
+		authFound := false
+		for _, logline := range logs.Lines {
+			if strings.EqualFold(logline.Message, "AUTH PLAIN AHRlc3QAcGFzc3dvcmQ=") &&
+				logline.Direction.From == "client" && logline.Direction.To == "server" {
+				authFound = true
+			}
+		}
+		if !authFound {
+			t.Errorf("logAuthData not working, no authentication info found in logs")
+		}
+	})
+}
diff --git a/client_test.go b/client_test.go
index 98a46b6..9d24293 100644
--- a/client_test.go
+++ b/client_test.go
@@ -268,21 +268,6 @@ func TestNewClient(t *testing.T) {
 				},
 				false, nil,
 			},
-			{
-				"WithLogger log.JSONlog", WithLogger(log.NewJSON(os.Stderr, log.LevelDebug)),
-				func(c *Client) error {
-					if c.logger == nil {
-						return errors.New("failed to set logger. Want logger bug got got nil")
-					}
-					loggerType := reflect.TypeOf(c.logger).String()
-					if loggerType != "*log.JSONlog" {
-						return fmt.Errorf("failed to set logger. Want logger type: %s, got: %s",
-							"*log.JSONlog", loggerType)
-					}
-					return nil
-				},
-				false, nil,
-			},
 			{
 				"WithHELO", WithHELO(hostname),
 				func(c *Client) error {
@@ -1759,42 +1744,6 @@ func TestClient_DialWithContext(t *testing.T) {
 			t.Fatalf("client has connection")
 		}
 	})
-	t.Run("connect with full debug logging and auth logging", func(t *testing.T) {
-		ctxDial, cancelDial := context.WithTimeout(ctx, time.Millisecond*500)
-		t.Cleanup(cancelDial)
-
-		logBuffer := bytes.NewBuffer(nil)
-		client, err := NewClient(DefaultHost, WithPort(serverPort), WithTLSPolicy(NoTLS),
-			WithDebugLog(), WithLogAuthData(), WithLogger(log.NewJSON(logBuffer, log.LevelDebug)),
-			WithSMTPAuth(SMTPAuthPlain), WithUsername("test"), WithPassword("password"))
-		if err != nil {
-			t.Fatalf("failed to create new client: %s", err)
-		}
-
-		if err = client.DialWithContext(ctxDial); err != nil {
-			t.Fatalf("failed to connect to the test server: %s", err)
-		}
-		t.Cleanup(func() {
-			if err = client.Close(); err != nil {
-				t.Errorf("failed to close the client: %s", err)
-			}
-		})
-
-		logs := parseJSONLog(t, logBuffer)
-		if len(logs.Lines) == 0 {
-			t.Errorf("failed to enable debug logging, but no logs were found")
-		}
-		authFound := false
-		for _, logline := range logs.Lines {
-			if strings.EqualFold(logline.Message, "AUTH PLAIN AHRlc3QAcGFzc3dvcmQ=") &&
-				logline.Direction.From == "client" && logline.Direction.To == "server" {
-				authFound = true
-			}
-		}
-		if !authFound {
-			t.Errorf("logAuthData not working, no authentication info found in logs")
-		}
-	})
 	t.Run("connect should fail on HELO", func(t *testing.T) {
 		ctxFail, cancelFail := context.WithCancel(ctx)
 		defer cancelFail()