Framework_4_0 preprocessor is necessary for legacy compatibility.

Server/Main.cs

@@ -28,7 +28,9 @@ using System.Reflection;
 using System.Runtime.InteropServices;
 using System.Text;
 using System.Threading;
+#if Framework_4_0
 using System.Threading.Tasks;
+#endif
 
 using Server;
 using Server.Accounting;
@@ -110,7 +112,11 @@ namespace Server
 		public static Thread Thread { get { return m_Thread; } }
 		public static MultiTextWriter MultiConsoleOut { get { return m_MultiConOut; } }
 
+#if Framework_4_0
 		public static readonly bool Is64Bit = Environment.Is64BitProcess;
+#else
+		public static readonly bool Is64Bit = (IntPtr.Size == 8);	//Returns the size for the current /process/
+#endif
 
 		private static bool m_MultiProcessor;
 		private static int m_ProcessorCount;
@@ -662,10 +668,17 @@ namespace Server
 			if( a == null )
 				return;
 
+#if Framework_4_0
 			Parallel.ForEach(a.GetTypes(), t => 
 				{
 					VerifyType(t);
 				});
+#else
+			foreach (Type t in a.GetTypes())
+			{
+				VerifyType(t);
+			}
+#endif
 		}
 	}