use an enum

ntfysh_client/SettingsModel.cs

@@ -2,12 +2,17 @@
 {
     public class SettingsModel
     {
+        public enum NotificationsType
+        {
+            NativeWindows,
+            CustomTray
+        }
+
         public uint Revision { get; set; }
         public decimal Timeout { get; set; }
         public decimal ReconnectAttempts { get; set; }
         public decimal ReconnectAttemptDelay { get; set; }
-        public bool UseNativeWindowsNotifications { get; set; }
-        public bool UseCustomTrayNotifications { get; set; }
+        public NotificationsType NotificationsMethod { get; set; }
         public bool CustomTrayNotificationsShowTimeoutBar { get; set; }
         public bool CustomTrayNotificationsShowInDarkMode { get; set; }
     }