diff --git a/internal/server/handlers_auth.go b/internal/server/handlers_auth.go
index 72833cc..88fc435 100644
--- a/internal/server/handlers_auth.go
+++ b/internal/server/handlers_auth.go
@@ -98,7 +98,7 @@ func (s *Server) PostLogin(c *gin.Context) {
 				Firstname: userData.Firstname,
 				Lastname:  userData.Lastname,
 				Phone:     userData.Phone,
-			}, s.wg.Cfg.DefaultDeviceName); err != nil {
+			}, s.wg.Cfg.GetDefaultDeviceName()); err != nil {
 				s.GetHandleError(c, http.StatusInternalServerError, "login error", "failed to update user data")
 				return
 			}
@@ -124,7 +124,7 @@ func (s *Server) PostLogin(c *gin.Context) {
 	sessionData.DeviceName = s.wg.Cfg.DeviceNames[0]
 
 	// Check if user already has a peer setup, if not create one
-	if err := s.CreateUserDefaultPeer(user.Email, s.wg.Cfg.DefaultDeviceName); err != nil {
+	if err := s.CreateUserDefaultPeer(user.Email, s.wg.Cfg.GetDefaultDeviceName()); err != nil {
 		// Not a fatal error, just log it...
 		logrus.Errorf("failed to automatically create vpn peer for %s: %v", sessionData.Email, err)
 	}
diff --git a/internal/wireguard/config.go b/internal/wireguard/config.go
index 027d928..ee84fe4 100644
--- a/internal/wireguard/config.go
+++ b/internal/wireguard/config.go
@@ -1,8 +1,17 @@
 package wireguard
 
+import "github.com/h44z/wg-portal/internal/common"
+
 type Config struct {
 	DeviceNames         []string `yaml:"devices" envconfig:"WG_DEVICES"`             // managed devices
-	DefaultDeviceName   string   `yaml:"devices" envconfig:"WG_DEFAULT_DEVICE"`      // this device is used for auto-created peers
+	DefaultDeviceName   string   `yaml:"devices" envconfig:"WG_DEFAULT_DEVICE"`      // this device is used for auto-created peers, use GetDefaultDeviceName() to access this field
 	ConfigDirectoryPath string   `yaml:"configDirectory" envconfig:"WG_CONFIG_PATH"` // optional, if set, updates will be written to this path, filename: <devicename>.conf
 	ManageIPAddresses   bool     `yaml:"manageIPAddresses" envconfig:"MANAGE_IPS"`   // handle ip-address setup of interface
 }
+
+func (c Config) GetDefaultDeviceName() string {
+	if c.DefaultDeviceName == "" || !common.ListContains(c.DeviceNames, c.DefaultDeviceName) {
+		return c.DeviceNames[0]
+	}
+	return c.DefaultDeviceName
+}
diff --git a/internal/wireguard/peermanager.go b/internal/wireguard/peermanager.go
index 099b491..11217dc 100644
--- a/internal/wireguard/peermanager.go
+++ b/internal/wireguard/peermanager.go
@@ -274,13 +274,23 @@ type PeerManager struct {
 }
 
 func NewPeerManager(db *gorm.DB, wg *Manager) (*PeerManager, error) {
-	um := &PeerManager{db: db, wg: wg}
+	pm := &PeerManager{db: db, wg: wg}
 
-	if err := um.db.AutoMigrate(&Peer{}, &Device{}); err != nil {
+	if err := pm.db.AutoMigrate(&Peer{}, &Device{}); err != nil {
 		return nil, errors.WithMessage(err, "failed to migrate peer database")
 	}
 
-	return um, nil
+	// check if peers without device name exist (from version <= 1.0.3), if so assign them to the default device.
+	peers := make([]Peer, 0)
+	pm.db.Find(&peers)
+	for i := range peers {
+		if peers[i].DeviceName == "" {
+			peers[i].DeviceName = wg.Cfg.GetDefaultDeviceName()
+			pm.db.Save(&peers[i])
+		}
+	}
+
+	return pm, nil
 }
 
 // InitFromPhysicalInterface read all WireGuard peers from the WireGuard interface configuration. If a peer does not