Index: src/Appender/AppenderSkeleton.cs
===================================================================
--- src/Appender/AppenderSkeleton.cs	(revision 1070780)
+++ src/Appender/AppenderSkeleton.cs	(working copy)
@@ -325,7 +325,7 @@
 				// on .NET 2.0 (and higher) and Mono (all profiles), 
 				// exceptions that do not derive from System.Exception will be
 				// wrapped in a RuntimeWrappedException by the runtime, and as
-				// such will be catched by the catch clause above
+				// such will be caught by the catch clause above
 				catch
 				{
 					// Catch handler for non System.Exception types
@@ -432,7 +432,7 @@
 				// on .NET 2.0 (and higher) and Mono (all profiles), 
 				// exceptions that do not derive from System.Exception will be
 				// wrapped in a RuntimeWrappedException by the runtime, and as
-				// such will be catched by the catch clause above
+				// such will be caught by the catch clause above
 				catch
 				{
 					// Catch handler for non System.Exception types
Index: src/Appender/AspNetTraceAppender.cs
===================================================================
--- src/Appender/AspNetTraceAppender.cs	(revision 1070780)
+++ src/Appender/AspNetTraceAppender.cs	(working copy)
@@ -19,7 +19,8 @@
 
 // .NET Compact Framework 1.0 has no support for ASP.NET
 // SSCLI 1.0 has no support for ASP.NET
-#if !NETCF && !SSCLI
+// Client Profile has no support for ASP.NET
+#if !NETCF && !SSCLI && !NET_CLIENT_PROFILE
 
 using System.Web;
 
Index: src/Appender/SmtpAppender.cs
===================================================================
--- src/Appender/SmtpAppender.cs	(revision 1070780)
+++ src/Appender/SmtpAppender.cs	(working copy)
@@ -460,7 +460,11 @@
                 }
                 if (!String.IsNullOrEmpty(m_replyTo))
                 {
+#if NET_4_0
+                    mailMessage.ReplyToList.Add(m_replyTo);
+#else
                     mailMessage.ReplyTo = new MailAddress(m_replyTo);
+#endif
                 }
                 mailMessage.Subject = m_subject;
                 mailMessage.Priority = m_mailPriority;
Index: src/AssemblyInfo.cs
===================================================================
--- src/AssemblyInfo.cs	(revision 1070780)
+++ src/AssemblyInfo.cs	(working copy)
@@ -39,6 +39,10 @@
 [assembly: System.Security.AllowPartiallyTrustedCallers]
 #endif
 
+#if (NET_4_0)
+[assembly: System.Security.SecurityRules(System.Security.SecurityRuleSet.Level1)]
+#endif
+
 //
 // General Information about an assembly is controlled through the following 
 // set of attributes. Change these attribute values to modify the information
@@ -51,6 +55,12 @@
 [assembly: AssemblyTitle("log4net for .NET Framework 1.0")]
 #elif (NET_1_1)
 [assembly: AssemblyTitle("log4net for .NET Framework 1.1")]
+#elif (NET_4_0 && NET_CLIENT_PROFILE)
+[assembly: AssemblyTitle("log4net for .NET Framework 4.0 Client Profile")]
+#elif (NET_4_0)
+[assembly: AssemblyTitle("log4net for .NET Framework 4.0")]
+#elif (NET_2_0 && NET_CLIENT_PROFILE)
+[assembly: AssemblyTitle("log4net for .NET Framework 3.5 Client Profile")]
 #elif (NET_2_0)
 [assembly: AssemblyTitle("log4net for .NET Framework 2.0")]
 #elif (NETCF_1_0)
Index: src/Config/XmlConfigurator.cs
===================================================================
--- src/Config/XmlConfigurator.cs	(revision 1070780)
+++ src/Config/XmlConfigurator.cs	(working copy)
@@ -728,7 +728,11 @@
 #elif NET_2_0
 					// Allow the DTD to specify entity includes
 					XmlReaderSettings settings = new XmlReaderSettings();
+#if NET_4_0
+                    settings.DtdProcessing = DtdProcessing.Parse;
+#else
 					settings.ProhibitDtd = false;
+#endif
 
 					// Create a reader over the input stream
 					XmlReader xmlReader = XmlReader.Create(configStream, settings);
Index: src/Layout/Pattern/AspNetCachePatternConverter.cs
===================================================================
--- src/Layout/Pattern/AspNetCachePatternConverter.cs	(revision 1070780)
+++ src/Layout/Pattern/AspNetCachePatternConverter.cs	(working copy)
@@ -19,7 +19,7 @@
 
 // .NET Compact Framework 1.0 has no support for ASP.NET
 // SSCLI 1.0 has no support for ASP.NET
-#if !NETCF && !SSCLI 
+#if !NETCF && !SSCLI && !NET_CLIENT_PROFILE
 
 using System.IO;
 using System.Web;
Index: src/Layout/Pattern/AspNetContextPatternConverter.cs
===================================================================
--- src/Layout/Pattern/AspNetContextPatternConverter.cs	(revision 1070780)
+++ src/Layout/Pattern/AspNetContextPatternConverter.cs	(working copy)
@@ -19,7 +19,7 @@
 
 // .NET Compact Framework 1.0 has no support for ASP.NET
 // SSCLI 1.0 has no support for ASP.NET
-#if !NETCF && !SSCLI 
+#if !NETCF && !SSCLI && !NET_CLIENT_PROFILE
 
 using System.IO;
 using System.Web;
Index: src/Layout/Pattern/AspNetPatternConverter.cs
===================================================================
--- src/Layout/Pattern/AspNetPatternConverter.cs	(revision 1070780)
+++ src/Layout/Pattern/AspNetPatternConverter.cs	(working copy)
@@ -19,7 +19,7 @@
 
 // .NET Compact Framework 1.0 has no support for ASP.NET
 // SSCLI 1.0 has no support for ASP.NET
-#if !NETCF && !SSCLI 
+#if !NETCF && !SSCLI && !NET_CLIENT_PROFILE
 
 using System.IO;
 using System.Web;
Index: src/Layout/Pattern/AspNetRequestPatternConverter.cs
===================================================================
--- src/Layout/Pattern/AspNetRequestPatternConverter.cs	(revision 1070780)
+++ src/Layout/Pattern/AspNetRequestPatternConverter.cs	(working copy)
@@ -19,7 +19,7 @@
 
 // .NET Compact Framework 1.0 has no support for ASP.NET
 // SSCLI 1.0 has no support for ASP.NET
-#if !NETCF && !SSCLI 
+#if !NETCF && !SSCLI && !NET_CLIENT_PROFILE
 
 using System.IO;
 using System.Web;
Index: src/Layout/Pattern/AspNetSessionPatternConverter.cs
===================================================================
--- src/Layout/Pattern/AspNetSessionPatternConverter.cs	(revision 1070780)
+++ src/Layout/Pattern/AspNetSessionPatternConverter.cs	(working copy)
@@ -19,7 +19,7 @@
 
 // .NET Compact Framework 1.0 has no support for ASP.NET
 // SSCLI 1.0 has no support for ASP.NET
-#if !NETCF && !SSCLI 
+#if !NETCF && !SSCLI && !NET_CLIENT_PROFILE
 
 using System.IO;
 using System.Web;
Index: src/Layout/PatternLayout.cs
===================================================================
--- src/Layout/PatternLayout.cs	(revision 1070780)
+++ src/Layout/PatternLayout.cs	(working copy)
@@ -816,7 +816,8 @@
 
 // .NET Compact Framework 1.0 has no support for ASP.NET
 // SSCLI 1.0 has no support for ASP.NET
-#if !NETCF && !SSCLI 
+// Client Profile has no support for ASP.NET
+#if !NETCF && !SSCLI && !NET_CLIENT_PROFILE
 			s_globalRulesRegistry.Add("aspnet-cache", typeof(AspNetCachePatternConverter));
 			s_globalRulesRegistry.Add("aspnet-context", typeof(AspNetContextPatternConverter));
 			s_globalRulesRegistry.Add("aspnet-request", typeof(AspNetRequestPatternConverter));