diff --git a/Renci.SshClient/Renci.SshNet/Sftp/Requests/SftpMkDirRequest.cs b/Renci.SshClient/Renci.SshNet/Sftp/Requests/SftpMkDirRequest.cs
index 9e3b6d09..567f2ad3 100644
--- a/Renci.SshClient/Renci.SshNet/Sftp/Requests/SftpMkDirRequest.cs
+++ b/Renci.SshClient/Renci.SshNet/Sftp/Requests/SftpMkDirRequest.cs
@@ -21,7 +21,7 @@ namespace Renci.SshNet.Sftp.Requests
             : base(requestId, statusAction)
         {
             this.Path = path;
-            this.Attributes = SftpFileAttributes.Empty;
+            this.Attributes = new SftpFileAttributes();
         }
 
         public SftpMkDirRequest(uint requestId, string path, SftpFileAttributes attributes, Action<SftpStatusResponse> statusAction)
diff --git a/Renci.SshClient/Renci.SshNet/Sftp/Requests/SftpOpenRequest.cs b/Renci.SshClient/Renci.SshNet/Sftp/Requests/SftpOpenRequest.cs
index b8fc5d61..63e63116 100644
--- a/Renci.SshClient/Renci.SshNet/Sftp/Requests/SftpOpenRequest.cs
+++ b/Renci.SshClient/Renci.SshNet/Sftp/Requests/SftpOpenRequest.cs
@@ -20,7 +20,7 @@ namespace Renci.SshNet.Sftp.Requests
         public SftpFileAttributes Attributes { get; private set; }
 
         public SftpOpenRequest(uint requestId, string fileName, Flags flags, Action<SftpHandleResponse> handleAction, Action<SftpStatusResponse> statusAction)
-            : this(requestId, fileName, flags, SftpFileAttributes.Empty, handleAction, statusAction)
+            : this(requestId, fileName, flags, new SftpFileAttributes(), handleAction, statusAction)
         {
         }
 
diff --git a/Renci.SshClient/Renci.SshNet/Sftp/SftpFileAttributes.cs b/Renci.SshClient/Renci.SshNet/Sftp/SftpFileAttributes.cs
index 87556a99..f485608f 100644
--- a/Renci.SshClient/Renci.SshNet/Sftp/SftpFileAttributes.cs
+++ b/Renci.SshClient/Renci.SshNet/Sftp/SftpFileAttributes.cs
@@ -60,6 +60,49 @@ namespace Renci.SshNet.Sftp
         private bool _isGroupIDBitSet;
         private bool _isStickyBitSet;
 
+        private DateTime _originalLastAccessTime;
+        private DateTime _originalLastWriteTime;
+        private long _originalSize;
+        private int _originalUserId;
+        private int _originalGroupId;
+        private uint _originalPermissions;
+        private IDictionary<string, string> _originalExtensions;
+
+        internal bool IsLastAccessTimeChanged
+        {
+            get { return this._originalLastAccessTime != this.LastAccessTime; }
+        }
+
+        internal bool IsLastWriteTimeChanged
+        {
+            get { return this._originalLastWriteTime != this.LastWriteTime; }
+        }
+
+        internal bool IsSizeChanged
+        {
+            get { return this._originalSize != this.Size; }
+        }
+
+        internal bool IsUserIdChanged
+        {
+            get { return this._originalUserId != this.UserId; }
+        }
+
+        internal bool IsGroupIdChanged
+        {
+            get { return this._originalGroupId != this.GroupId; }
+        }
+
+        internal bool IsPermissionsChanged
+        {
+            get { return this._originalPermissions != this.Permissions; }
+        }
+
+        internal bool IsExtensionsChanged
+        {
+            get { return this._originalExtensions != null && this.Extensions != null && !this._originalExtensions.SequenceEqual(this.Extensions); }
+        }
+
         /// <summary>
         /// Gets or sets the time the current file or directory was last accessed.
         /// </summary>
@@ -304,7 +347,6 @@ namespace Renci.SshNet.Sftp
 
                 return permission;
             }
-
             private set
             {
                 this._isBitFiledsBitSet = ((value & S_IFMT) == S_IFMT);
@@ -349,27 +391,19 @@ namespace Renci.SshNet.Sftp
             }
         }
 
-        private static SftpFileAttributes _empty = new SftpFileAttributes(DateTime.MinValue, DateTime.MinValue, -1, -1, -1, 0, null);
-        /// <summary>
-        /// Gets the empty SftpFileAttributes instance.
-        /// </summary>
-        public static SftpFileAttributes Empty
+        internal SftpFileAttributes()
         {
-            get
-            {
-                return SftpFileAttributes._empty;
-            }
         }
 
         internal SftpFileAttributes(DateTime lastAccessTime, DateTime lastWriteTime, long size, int userId, int groupId, uint permissions, IDictionary<string, string> extensions)
         {
-            this.LastAccessTime = lastAccessTime;
-            this.LastWriteTime = lastWriteTime;
-            this.Size = size;
-            this.UserId = userId;
-            this.GroupId = groupId;
-            this.Permissions = permissions;
-            this.Extensions = extensions;
+            this.LastAccessTime = this._originalLastAccessTime = lastAccessTime;
+            this.LastWriteTime = this._originalLastWriteTime = lastWriteTime;
+            this.Size = this._originalSize = size;
+            this.UserId = this._originalUserId = userId;
+            this.GroupId = this._originalGroupId = groupId;
+            this.Permissions = this._originalPermissions = permissions;
+            this.Extensions = this._originalExtensions = extensions;
         }
 
         /// <summary>
@@ -383,7 +417,7 @@ namespace Renci.SshNet.Sftp
                 throw new ArgumentOutOfRangeException("mode");
             }
 
-            var modeBytes = mode.ToString(CultureInfo.InvariantCulture).PadLeft(3,'0').ToArray();
+            var modeBytes = mode.ToString(CultureInfo.InvariantCulture).PadLeft(3, '0').ToArray();
 
             var permission = (modeBytes[0] & 0x0F) * 8 * 8 + (modeBytes[1] & 0x0F) * 8 + (modeBytes[2] & 0x0F);
 
diff --git a/Renci.SshClient/Renci.SshNet/Sftp/SftpMessage.cs b/Renci.SshClient/Renci.SshNet/Sftp/SftpMessage.cs
index dfaf20dd..522dc073 100644
--- a/Renci.SshClient/Renci.SshNet/Sftp/SftpMessage.cs
+++ b/Renci.SshClient/Renci.SshNet/Sftp/SftpMessage.cs
@@ -94,50 +94,50 @@ namespace Renci.SshNet.Sftp
             {
                 UInt32 flag = 0;
 
-                if (attributes.Size > -1)
+                if (attributes.IsSizeChanged && attributes.IsRegularFile)
                 {
                     flag |= 0x00000001;
                 }
 
-                if (attributes.UserId > -1 && attributes.GroupId > -1)
+                if (attributes.IsUserIdChanged|| attributes.IsGroupIdChanged)
                 {
                     flag |= 0x00000002;
                 }
 
-                if (attributes.Permissions > 0)
+                if (attributes.IsPermissionsChanged)
                 {
                     flag |= 0x00000004;
                 }
 
-                if (attributes.LastAccessTime > DateTime.MinValue && attributes.LastWriteTime > DateTime.MinValue)
+                if (attributes.IsLastAccessTimeChanged || attributes.IsLastWriteTimeChanged)
                 {
                     flag |= 0x00000008;
                 }
 
-                if (attributes.Extensions != null)
+                if (attributes.IsExtensionsChanged)
                 {
                     flag |= 0x80000000;
                 }
 
                 this.Write(flag);
 
-                if (attributes.Size > -1)
+                if (attributes.IsSizeChanged && attributes.IsRegularFile)
                 {
                     this.Write((UInt64)attributes.Size);
                 }
 
-                if (attributes.UserId > -1 && attributes.GroupId > -1)
+                if (attributes.IsUserIdChanged|| attributes.IsGroupIdChanged)
                 {
                     this.Write((UInt32)attributes.UserId);
                     this.Write((UInt32)attributes.GroupId);
                 }
 
-                if (attributes.Permissions > 0)
+                if (attributes.IsPermissionsChanged)
                 {
                     this.Write(attributes.Permissions);
                 }
 
-                if (attributes.LastAccessTime > DateTime.MinValue && attributes.LastWriteTime > DateTime.MinValue)
+                if (attributes.IsLastAccessTimeChanged || attributes.IsLastWriteTimeChanged)
                 {
                     uint time = (uint)(attributes.LastAccessTime.ToFileTime() / 10000000 - 11644473600);
                     this.Write(time);
@@ -145,7 +145,7 @@ namespace Renci.SshNet.Sftp
                     this.Write(time);
                 }
 
-                if (attributes.Extensions != null)
+                if (attributes.IsExtensionsChanged)
                 {
                     this.Write(attributes.Extensions);
                 }