diff --git a/src/Discord.Net/DiscordConfig.cs b/src/Discord.Net/DiscordConfig.cs
index b809ec8e2..15157e7ff 100644
--- a/src/Discord.Net/DiscordConfig.cs
+++ b/src/Discord.Net/DiscordConfig.cs
@@ -5,6 +5,13 @@ using System.Text;
 
 namespace Discord
 {
+    public enum DiscordMode
+    {
+        /// <summary> Enable bot-only functions. Use this mode if you are creating a bot, automated application, or interface. </summary>
+        Bot = 0,
+        /// <summary> Enables client-only functions. Use this mode if you are creating a custom client. </summary>
+        Client
+    }
 	public enum LogSeverity : byte
 	{
 		Error = 1,
@@ -45,11 +52,13 @@ namespace Discord
         /// <summary> Enables or disables the default event logger. </summary>
         public bool LogEvents { get { return _logEvents; } set { SetValue(ref _logEvents, value); } }
         private bool _logEvents = true;
+        /// <summary> Specifies the mode that this application should run in. </summary>
+        public DiscordMode Mode { get { return _mode; } set { SetValue(ref _mode, value); } }
+        private DiscordMode _mode = DiscordMode.Bot;
 
         /// <summary> User Agent string to use when connecting to Discord. </summary>
         [JsonIgnore]
-        public string UserAgent { get { return _userAgent; } }
-        private string _userAgent;
+        public string UserAgent { get; private set; }
 
         //Rest
 
@@ -120,7 +129,7 @@ namespace Discord
                 builder.Append(' ');
             }
             builder.Append($"DiscordBot ({LibUrl}, v{LibVersion})");
-            _userAgent = builder.ToString();
+            UserAgent = builder.ToString();
         }
     }
 }
diff --git a/src/Discord.Net/Models/Message.cs b/src/Discord.Net/Models/Message.cs
index 0e6fe719a..665ac8397 100644
--- a/src/Discord.Net/Models/Message.cs
+++ b/src/Discord.Net/Models/Message.cs
@@ -340,6 +340,9 @@ namespace Discord
         
         public Task Acknowledge()
         {
+            if (Client.Config.Mode != DiscordMode.Client)
+                throw new InvalidOperationException("Message.Acknowledge may only be used in Client mode.");
+
             if (User.Id != Client.CurrentUser.Id)
                 return Client.ClientAPI.Send(new AckMessageRequest(Channel.Id, Id));
             else