diff --git a/CHANGELOG.md b/CHANGELOG.md
index e408385c..6262c21d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -12,6 +12,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 ### Fixed
 - #1610: Menu bar changes to english when cancelling options form
 - #1595: Unhandled exception when trying to browse through non existent multi ssh history with keyboard key strokes
+- #1589: Update SQL tables instead of rewriting them
 - #1337: Unhandled exception after closing mRemoteNG
 - #359: Making a VNC connection to an unreachable host causes the application to not respond for 20-30 seconds
 
diff --git a/CREDITS.md b/CREDITS.md
index 43a1fa4c..dfc75b7c 100644
--- a/CREDITS.md
+++ b/CREDITS.md
@@ -26,6 +26,7 @@ Stephan (http://github.com/st-schuler)
 Aleksey Reytsman (http://github.com/areytsman)  
 Cristian Abelleira (http://github.com/CrAbelleira)  
 http://github.com/MitchellBot
+Filippo Ferrazini (http://github.com/Filippo125)
 
 ## Past Contributors
 Felix Deimel - mRemote original developer  
diff --git a/mRemoteV1/Config/Connections/SqlConnectionsSaver.cs b/mRemoteV1/Config/Connections/SqlConnectionsSaver.cs
index a3a24dd1..f858ccae 100644
--- a/mRemoteV1/Config/Connections/SqlConnectionsSaver.cs
+++ b/mRemoteV1/Config/Connections/SqlConnectionsSaver.cs
@@ -153,14 +153,16 @@ namespace mRemoteNG.Config.Connections
 
         private void UpdateConnectionsTable(RootNodeInfo rootTreeNode, IDatabaseConnector databaseConnector)
         {
+            var dataProvider = new SqlDataProvider(databaseConnector);
+            var currentDataTable = dataProvider.Load();
+
             var cryptoProvider = new LegacyRijndaelCryptographyProvider();
             var serializer = new DataTableSerializer(_saveFilter, cryptoProvider,
                                                      rootTreeNode.PasswordString.ConvertToSecureString());
+            serializer.SetSourceDataTable(currentDataTable);
             var dataTable = serializer.Serialize(rootTreeNode);
-            var dataProvider = new SqlDataProvider(databaseConnector);
-
-            var dbQuery = databaseConnector.DbCommand("DELETE FROM tblCons");
-            dbQuery.ExecuteNonQuery();
+            //var dbQuery = databaseConnector.DbCommand("DELETE FROM tblCons");
+            //dbQuery.ExecuteNonQuery();
 
             dataProvider.Save(dataTable);
         }
diff --git a/mRemoteV1/Config/DataProviders/SqlDataProvider.cs b/mRemoteV1/Config/DataProviders/SqlDataProvider.cs
index 68e43324..93f73f29 100644
--- a/mRemoteV1/Config/DataProviders/SqlDataProvider.cs
+++ b/mRemoteV1/Config/DataProviders/SqlDataProvider.cs
@@ -44,12 +44,31 @@ namespace mRemoteNG.Config.DataProviders
                 OpenConnection();
             if (DatabaseConnector.GetType() == typeof(MSSqlDatabaseConnector))
             {
-                using (var sqlBulkCopy = new SqlBulkCopy((SqlConnection)DatabaseConnector.DbConnection()))
+                SqlConnection sqlConnection = (SqlConnection)DatabaseConnector.DbConnection();
+                using (SqlTransaction transaction = sqlConnection.BeginTransaction(System.Data.IsolationLevel.Serializable))
                 {
-                    foreach (DataColumn col in dataTable.Columns)
-                        sqlBulkCopy.ColumnMappings.Add(col.ColumnName, col.ColumnName);
-                    sqlBulkCopy.DestinationTableName = "dbo.tblCons";
-                    sqlBulkCopy.WriteToServer(dataTable);
+                    using (SqlCommand sqlCommand = new SqlCommand())
+                    {
+                        sqlCommand.Connection = sqlConnection;
+                        sqlCommand.Transaction = transaction;
+                        sqlCommand.CommandText = "SELECT * FROM tblCons";
+                        using (SqlDataAdapter dataAdpater = new SqlDataAdapter())
+                        {
+                            dataAdpater.SelectCommand = sqlCommand;
+
+                            SqlCommandBuilder builder = new SqlCommandBuilder(dataAdpater);
+                            // Avoid optimistic concurrency, check if it is necessary.
+                            builder.ConflictOption = ConflictOption.OverwriteChanges;
+
+                            dataAdpater.UpdateCommand = builder.GetUpdateCommand();
+
+                            dataAdpater.DeleteCommand = builder.GetDeleteCommand();
+                            dataAdpater.InsertCommand = builder.GetInsertCommand();
+
+                            dataAdpater.Update(dataTable);
+                            transaction.Commit();
+                        }
+                    }
                 }
 
             }
diff --git a/mRemoteV1/Config/Serializers/ConnectionSerializers/MsSql/DataTableSerializer.cs b/mRemoteV1/Config/Serializers/ConnectionSerializers/MsSql/DataTableSerializer.cs
index 489c6c5a..6ebc3bc0 100644
--- a/mRemoteV1/Config/Serializers/ConnectionSerializers/MsSql/DataTableSerializer.cs
+++ b/mRemoteV1/Config/Serializers/ConnectionSerializers/MsSql/DataTableSerializer.cs
@@ -5,6 +5,7 @@ using mRemoteNG.Tools;
 using mRemoteNG.Tree;
 using mRemoteNG.Tree.Root;
 using System;
+using System.Collections.Generic;
 using System.Data;
 using System.Linq;
 using System.Security;
@@ -13,14 +14,17 @@ namespace mRemoteNG.Config.Serializers.MsSql
 {
     public class DataTableSerializer : ISerializer<ConnectionInfo, DataTable>
     {
+        public readonly int DELETE = 0;
         private readonly ICryptographyProvider _cryptographyProvider;
         private readonly SecureString _encryptionKey;
         private DataTable _dataTable;
+        private DataTable _sourceDataTable;
+        private Dictionary<string, int> sourcePrimaryKeyDict = new Dictionary<string, int>();
         private const string TableName = "tblCons";
         private readonly SaveFilter _saveFilter;
         private int _currentNodeIndex;
 
-        public Version Version { get; } = new Version(2, 7);
+        public Version Version { get; } = new Version(2, 8);
 
         public DataTableSerializer(SaveFilter saveFilter,
                                    ICryptographyProvider cryptographyProvider,
@@ -31,6 +35,11 @@ namespace mRemoteNG.Config.Serializers.MsSql
             _encryptionKey = encryptionKey.ThrowIfNull(nameof(encryptionKey));
         }
 
+        public void SetSourceDataTable(DataTable sourceDataTable)
+        {
+            _sourceDataTable = sourceDataTable;
+        }
+
 
         public DataTable Serialize(ConnectionTreeModel connectionTreeModel)
         {
@@ -51,15 +60,33 @@ namespace mRemoteNG.Config.Serializers.MsSql
         {
             _dataTable = BuildTable();
             _currentNodeIndex = 0;
+            // Register add or update row
             SerializeNodesRecursive(serializationTarget);
+            var entryToDelete = sourcePrimaryKeyDict.Keys.ToList();
+            foreach( var entry in entryToDelete)
+            {
+                _dataTable.Rows.Find(entry).Delete();
+            }
             return _dataTable;
         }
 
         private DataTable BuildTable()
         {
-            var dataTable = new DataTable(TableName);
-            CreateSchema(dataTable);
-            SetPrimaryKey(dataTable);
+            DataTable dataTable;
+            if (_sourceDataTable != null)
+            {
+                dataTable = _sourceDataTable;
+            }else
+            {
+                dataTable = new DataTable(TableName);
+
+            }
+            if (dataTable.Columns.Count == 0) CreateSchema(dataTable);
+            if (dataTable.PrimaryKey.Length == 0 ) SetPrimaryKey(dataTable);
+            foreach(DataRow row in dataTable.Rows)
+            {
+                sourcePrimaryKeyDict.Add((string)row["ConstantID"], DELETE);
+            }
             return dataTable;
         }
 
@@ -216,14 +243,244 @@ namespace mRemoteNG.Config.Serializers.MsSql
                 SerializeNodesRecursive(child);
         }
 
+        public bool isRowUpdated(ConnectionInfo connectionInfo, DataRow dataRow)
+        {
+            var isFieldNotChange = dataRow["Name"].Equals(connectionInfo.Name) &&
+            dataRow["Type"].Equals(connectionInfo.GetTreeNodeType().ToString()) &&
+            dataRow["ParentID"].Equals(connectionInfo.Parent?.ConstantID ?? "") &&
+            dataRow["PositionID"].Equals(_currentNodeIndex) &&
+            dataRow["Expanded"].Equals(false) &&
+            dataRow["Description"].Equals(connectionInfo.Description) &&
+            dataRow["Icon"].Equals(connectionInfo.Icon) &&
+            dataRow["Panel"].Equals(connectionInfo.Panel) &&
+            dataRow["Username"].Equals(_saveFilter.SaveUsername ? connectionInfo.Username : "") &&
+            dataRow["DomainName"].Equals(_saveFilter.SaveDomain ? connectionInfo.Domain : "");
+
+            isFieldNotChange = isFieldNotChange && dataRow["Hostname"].Equals(connectionInfo.Hostname);
+             isFieldNotChange = isFieldNotChange && dataRow["VmId"].Equals(connectionInfo.VmId);
+            isFieldNotChange = isFieldNotChange && dataRow["Protocol"].Equals(connectionInfo.Protocol.ToString());
+            isFieldNotChange = isFieldNotChange && dataRow["PuttySession"].Equals(connectionInfo.PuttySession);
+            isFieldNotChange = isFieldNotChange &&
+            dataRow["Port"].Equals(connectionInfo.Port);
+            isFieldNotChange = isFieldNotChange &&
+            dataRow["ConnectToConsole"].Equals(connectionInfo.UseConsoleSession);
+            isFieldNotChange = isFieldNotChange &&
+            dataRow["UseCredSsp"].Equals(connectionInfo.UseCredSsp);
+            isFieldNotChange = isFieldNotChange &&
+            dataRow["UseVmId"].Equals(connectionInfo.UseVmId);
+            isFieldNotChange = isFieldNotChange &&
+            dataRow["UseEnhancedMode"].Equals(connectionInfo.UseEnhancedMode);
+            isFieldNotChange = isFieldNotChange &&
+            dataRow["RenderingEngine"].Equals(connectionInfo.RenderingEngine.ToString());
+            isFieldNotChange = isFieldNotChange &&
+            dataRow["ICAEncryptionStrength"].Equals(connectionInfo.ICAEncryptionStrength.ToString());
+            isFieldNotChange = isFieldNotChange &&
+            dataRow["RDPAuthenticationLevel"].Equals(connectionInfo.RDPAuthenticationLevel.ToString());
+            isFieldNotChange = isFieldNotChange &&
+            dataRow["RDPMinutesToIdleTimeout"].Equals(connectionInfo.RDPMinutesToIdleTimeout);
+            isFieldNotChange = isFieldNotChange &&
+            dataRow["RDPAlertIdleTimeout"].Equals(connectionInfo.RDPAlertIdleTimeout);
+            isFieldNotChange = isFieldNotChange &&
+            dataRow["LoadBalanceInfo"].Equals(connectionInfo.LoadBalanceInfo);
+            isFieldNotChange = isFieldNotChange &&
+            dataRow["Colors"].Equals(connectionInfo.Colors.ToString());
+            isFieldNotChange = isFieldNotChange &&
+            dataRow["Resolution"].Equals(connectionInfo.Resolution.ToString());
+            isFieldNotChange = isFieldNotChange &&
+            dataRow["AutomaticResize"].Equals(connectionInfo.AutomaticResize);
+            isFieldNotChange = isFieldNotChange &&
+            dataRow["DisplayWallpaper"].Equals(connectionInfo.DisplayWallpaper) &&
+             dataRow["DisplayThemes"].Equals(connectionInfo.DisplayThemes) &&
+             dataRow["EnableFontSmoothing"].Equals(connectionInfo.EnableFontSmoothing) &&
+             dataRow["EnableDesktopComposition"].Equals(connectionInfo.EnableDesktopComposition) &&
+             dataRow["CacheBitmaps"].Equals(connectionInfo.CacheBitmaps) &&
+             dataRow["RedirectDiskDrives"].Equals(connectionInfo.RedirectDiskDrives) &&
+             dataRow["RedirectPorts"].Equals(connectionInfo.RedirectPorts) &&
+             dataRow["RedirectPrinters"].Equals(connectionInfo.RedirectPrinters) &&
+             dataRow["RedirectClipboard"].Equals(connectionInfo.RedirectClipboard) &&
+             dataRow["RedirectSmartCards"].Equals(connectionInfo.RedirectSmartCards) &&
+             dataRow["RedirectSound"].Equals(connectionInfo.RedirectSound.ToString()) &&
+             dataRow["SoundQuality"].Equals(connectionInfo.SoundQuality.ToString()) &&
+             dataRow["RedirectAudioCapture"].Equals(connectionInfo.RedirectAudioCapture) &&
+             dataRow["RedirectKeys"].Equals(connectionInfo.RedirectKeys);
+
+            isFieldNotChange = isFieldNotChange &&
+             dataRow["Connected"].Equals(false) && // TODO: this column can eventually be removed. we now save this property locally
+             dataRow["PreExtApp"].Equals(connectionInfo.PreExtApp) &&
+             dataRow["PostExtApp"].Equals(connectionInfo.PostExtApp) &&
+             dataRow["MacAddress"].Equals(connectionInfo.MacAddress) &&
+             dataRow["UserField"].Equals(connectionInfo.UserField) &&
+             dataRow["ExtApp"].Equals(connectionInfo.ExtApp) &&
+             dataRow["VNCCompression"].Equals(connectionInfo.VNCCompression.ToString()) &&
+             dataRow["VNCEncoding"].Equals(connectionInfo.VNCEncoding.ToString()) &&
+             dataRow["VNCAuthMode"].Equals(connectionInfo.VNCAuthMode.ToString()) &&
+             dataRow["VNCProxyType"].Equals(connectionInfo.VNCProxyType.ToString()) &&
+             dataRow["VNCProxyIP"].Equals(connectionInfo.VNCProxyIP) &&
+             dataRow["VNCProxyPort"].Equals(connectionInfo.VNCProxyPort) &&
+             dataRow["VNCProxyUsername"].Equals(connectionInfo.VNCProxyUsername) &&
+             dataRow["VNCColors"].Equals(connectionInfo.VNCColors.ToString()) &&
+             dataRow["VNCSmartSizeMode"].Equals(connectionInfo.VNCSmartSizeMode.ToString()) &&
+             dataRow["VNCViewOnly"].Equals(connectionInfo.VNCViewOnly) &&
+             dataRow["RDGatewayUsageMethod"].Equals(connectionInfo.RDGatewayUsageMethod.ToString()) &&
+             dataRow["RDGatewayHostname"].Equals(connectionInfo.RDGatewayHostname) &&
+             dataRow["RDGatewayUseConnectionCredentials"].Equals(connectionInfo.RDGatewayUseConnectionCredentials.ToString()) &&
+             dataRow["RDGatewayUsername"].Equals(connectionInfo.RDGatewayUsername) &&
+             
+             dataRow["RDGatewayDomain"].Equals(connectionInfo.RDGatewayDomain) &&
+             dataRow["RdpVersion"].Equals(connectionInfo.RdpVersion.ToString());
+
+            var isInheritanceFieldNotChange = false;
+            if (_saveFilter.SaveInheritance)
+            {
+                isInheritanceFieldNotChange = (dataRow["InheritCacheBitmaps"].Equals(connectionInfo.Inheritance.CacheBitmaps) &&
+                dataRow["InheritColors"].Equals(connectionInfo.Inheritance.Colors) &&
+                dataRow["InheritDescription"].Equals(connectionInfo.Inheritance.Description) &&
+                dataRow["InheritDisplayThemes"].Equals(connectionInfo.Inheritance.DisplayThemes) &&
+                dataRow["InheritDisplayWallpaper"].Equals(connectionInfo.Inheritance.DisplayWallpaper) &&
+                dataRow["InheritEnableFontSmoothing"].Equals(connectionInfo.Inheritance.EnableFontSmoothing) &&
+                dataRow["InheritEnableDesktopComposition"].Equals(connectionInfo.Inheritance.EnableDesktopComposition) &&
+                dataRow["InheritDomain"].Equals(connectionInfo.Inheritance.Domain) &&
+                dataRow["InheritIcon"].Equals(connectionInfo.Inheritance.Icon) &&
+                dataRow["InheritPanel"].Equals(connectionInfo.Inheritance.Panel) &&
+                dataRow["InheritPassword"].Equals(connectionInfo.Inheritance.Password) &&
+                dataRow["InheritPort"].Equals(connectionInfo.Inheritance.Port) &&
+                dataRow["InheritProtocol"].Equals(connectionInfo.Inheritance.Protocol) &&
+                dataRow["InheritPuttySession"].Equals(connectionInfo.Inheritance.PuttySession) &&
+                dataRow["InheritRedirectDiskDrives"].Equals(connectionInfo.Inheritance.RedirectDiskDrives) &&
+                dataRow["InheritRedirectKeys"].Equals(connectionInfo.Inheritance.RedirectKeys) &&
+                dataRow["InheritRedirectPorts"].Equals(connectionInfo.Inheritance.RedirectPorts) &&
+                dataRow["InheritRedirectPrinters"].Equals(connectionInfo.Inheritance.RedirectPrinters) &&
+                dataRow["InheritRedirectClipboard"].Equals(connectionInfo.Inheritance.RedirectClipboard) &&
+                dataRow["InheritRedirectSmartCards"].Equals(connectionInfo.Inheritance.RedirectSmartCards) &&
+                dataRow["InheritRedirectSound"].Equals(connectionInfo.Inheritance.RedirectSound) &&
+                dataRow["InheritSoundQuality"].Equals(connectionInfo.Inheritance.SoundQuality) &&
+                dataRow["InheritRedirectAudioCapture"].Equals(connectionInfo.Inheritance.RedirectAudioCapture) &&
+                dataRow["InheritResolution"].Equals(connectionInfo.Inheritance.Resolution) &&
+                dataRow["InheritAutomaticResize"].Equals(connectionInfo.Inheritance.AutomaticResize) &&
+                dataRow["InheritUseConsoleSession"].Equals(connectionInfo.Inheritance.UseConsoleSession) &&
+                dataRow["InheritUseCredSsp"].Equals(connectionInfo.Inheritance.UseCredSsp) &&
+                dataRow["InheritRenderingEngine"].Equals(connectionInfo.Inheritance.RenderingEngine) &&
+                dataRow["InheritUsername"].Equals(connectionInfo.Inheritance.Username) &&
+                dataRow["InheritVmId"].Equals(connectionInfo.Inheritance.VmId) &&
+                dataRow["InheritUseVmId"].Equals(connectionInfo.Inheritance.UseVmId) &&
+                dataRow["InheritUseEnhancedMode"].Equals(connectionInfo.Inheritance.UseEnhancedMode) &&
+                dataRow["InheritICAEncryptionStrength"].Equals(connectionInfo.Inheritance.ICAEncryptionStrength) &&
+                dataRow["InheritRDPAuthenticationLevel"].Equals(connectionInfo.Inheritance.RDPAuthenticationLevel) &&
+                dataRow["InheritRDPMinutesToIdleTimeout"].Equals(connectionInfo.Inheritance.RDPMinutesToIdleTimeout) &&
+                dataRow["InheritRDPAlertIdleTimeout"].Equals(connectionInfo.Inheritance.RDPAlertIdleTimeout) &&
+                dataRow["InheritLoadBalanceInfo"].Equals(connectionInfo.Inheritance.LoadBalanceInfo) &&
+                dataRow["InheritPreExtApp"].Equals(connectionInfo.Inheritance.PreExtApp) &&
+                dataRow["InheritPostExtApp"].Equals(connectionInfo.Inheritance.PostExtApp) &&
+                dataRow["InheritMacAddress"].Equals(connectionInfo.Inheritance.MacAddress) &&
+                dataRow["InheritUserField"].Equals(connectionInfo.Inheritance.UserField) &&
+                dataRow["InheritExtApp"].Equals(connectionInfo.Inheritance.ExtApp) &&
+                dataRow["InheritVNCCompression"].Equals(connectionInfo.Inheritance.VNCCompression) &&
+                dataRow["InheritVNCEncoding"].Equals(connectionInfo.Inheritance.VNCEncoding) &&
+                dataRow["InheritVNCAuthMode"].Equals(connectionInfo.Inheritance.VNCAuthMode) &&
+                dataRow["InheritVNCProxyType"].Equals(connectionInfo.Inheritance.VNCProxyType) &&
+                dataRow["InheritVNCProxyIP"].Equals(connectionInfo.Inheritance.VNCProxyIP) &&
+                dataRow["InheritVNCProxyPort"].Equals(connectionInfo.Inheritance.VNCProxyPort) &&
+                dataRow["InheritVNCProxyUsername"].Equals(connectionInfo.Inheritance.VNCProxyUsername) &&
+                dataRow["InheritVNCProxyPassword"].Equals(connectionInfo.Inheritance.VNCProxyPassword) &&
+                dataRow["InheritVNCColors"].Equals(connectionInfo.Inheritance.VNCColors) &&
+                dataRow["InheritVNCSmartSizeMode"].Equals(connectionInfo.Inheritance.VNCSmartSizeMode) &&
+                dataRow["InheritVNCViewOnly"].Equals(connectionInfo.Inheritance.VNCViewOnly) &&
+                dataRow["InheritRDGatewayUsageMethod"].Equals(connectionInfo.Inheritance.RDGatewayUsageMethod) &&
+                dataRow["InheritRDGatewayHostname"].Equals(connectionInfo.Inheritance.RDGatewayHostname) &&
+                dataRow["InheritRDGatewayUseConnectionCredentials"].Equals(connectionInfo.Inheritance.RDGatewayUseConnectionCredentials) &&
+                dataRow["InheritRDGatewayUsername"].Equals(connectionInfo.Inheritance.RDGatewayUsername) &&
+                dataRow["InheritRDGatewayPassword"].Equals(connectionInfo.Inheritance.RDGatewayPassword) &&
+                dataRow["InheritRDGatewayDomain"].Equals(connectionInfo.Inheritance.RDGatewayDomain) &&
+                dataRow["InheritRdpVersion"].Equals(connectionInfo.Inheritance.RdpVersion));
+            }
+            else
+            {
+                isInheritanceFieldNotChange = (dataRow["InheritCacheBitmaps"].Equals(false) &&
+                dataRow["InheritColors"].Equals(false) &&
+                dataRow["InheritDescription"].Equals(false) &&
+                dataRow["InheritDisplayThemes"].Equals(false) &&
+                dataRow["InheritDisplayWallpaper"].Equals(false) &&
+                dataRow["InheritEnableFontSmoothing"].Equals(false) &&
+                dataRow["InheritEnableDesktopComposition"].Equals(false) &&
+                dataRow["InheritDomain"].Equals(false) &&
+                dataRow["InheritIcon"].Equals(false) &&
+                dataRow["InheritPanel"].Equals(false) &&
+                dataRow["InheritPassword"].Equals(false) &&
+                dataRow["InheritPort"].Equals(false) &&
+                dataRow["InheritProtocol"].Equals(false) &&
+                dataRow["InheritPuttySession"].Equals(false) &&
+                dataRow["InheritRedirectDiskDrives"].Equals(false) &&
+                dataRow["InheritRedirectKeys"].Equals(false) &&
+                dataRow["InheritRedirectPorts"].Equals(false) &&
+                dataRow["InheritRedirectPrinters"].Equals(false) &&
+                dataRow["InheritRedirectClipboard"].Equals(false) &&
+                dataRow["InheritRedirectSmartCards"].Equals(false) &&
+                dataRow["InheritRedirectSound"].Equals(false) &&
+                dataRow["InheritSoundQuality"].Equals(false) &&
+                dataRow["InheritRedirectAudioCapture"].Equals(false) &&
+                dataRow["InheritResolution"].Equals(false) &&
+                dataRow["InheritAutomaticResize"].Equals(false) &&
+                dataRow["InheritUseConsoleSession"].Equals(false) &&
+                dataRow["InheritUseCredSsp"].Equals(false) &&
+                dataRow["InheritRenderingEngine"].Equals(false) &&
+                dataRow["InheritUsername"].Equals(false) &&
+                dataRow["InheritICAEncryptionStrength"].Equals(false) &&
+                dataRow["InheritRDPAuthenticationLevel"].Equals(false) &&
+                dataRow["InheritRDPMinutesToIdleTimeout"].Equals(false) &&
+                dataRow["InheritRDPAlertIdleTimeout"].Equals(false) &&
+                dataRow["InheritLoadBalanceInfo"].Equals(false) &&
+                dataRow["InheritPreExtApp"].Equals(false) &&
+                dataRow["InheritPostExtApp"].Equals(false) &&
+                dataRow["InheritMacAddress"].Equals(false) &&
+                dataRow["InheritUserField"].Equals(false) &&
+                dataRow["InheritExtApp"].Equals(false) &&
+                dataRow["InheritVNCCompression"].Equals(false) &&
+                dataRow["InheritVNCEncoding"].Equals(false) &&
+                dataRow["InheritVNCAuthMode"].Equals(false) &&
+                dataRow["InheritVNCProxyType"].Equals(false) &&
+                dataRow["InheritVNCProxyIP"].Equals(false) &&
+                dataRow["InheritVNCProxyPort"].Equals(false) &&
+                dataRow["InheritVNCProxyUsername"].Equals(false) &&
+                dataRow["InheritVNCProxyPassword"].Equals(false) &&
+                dataRow["InheritVNCColors"].Equals(false) &&
+                dataRow["InheritVNCSmartSizeMode"].Equals(false) &&
+                dataRow["InheritVNCViewOnly"].Equals(false) &&
+                dataRow["InheritRDGatewayUsageMethod"].Equals(false) &&
+                dataRow["InheritRDGatewayHostname"].Equals(false) &&
+                dataRow["InheritRDGatewayUseConnectionCredentials"].Equals(false) &&
+                dataRow["InheritRDGatewayUsername"].Equals(false) &&
+                dataRow["InheritRDGatewayPassword"].Equals(false) &&
+                dataRow["InheritRDGatewayDomain"].Equals(false) &&
+                dataRow["InheritRdpVersion"].Equals(false));
+            }
+
+            var pwd = dataRow["Password"].Equals(_saveFilter.SavePassword ? _cryptographyProvider.Encrypt(connectionInfo.Password, _encryptionKey) : "") &&
+                      dataRow["VNCProxyPassword"].Equals(_cryptographyProvider.Encrypt(connectionInfo.VNCProxyPassword, _encryptionKey)) &&
+                      dataRow["RDGatewayPassword"].Equals(_cryptographyProvider.Encrypt(connectionInfo.RDGatewayPassword, _encryptionKey));
+            return !(pwd && isFieldNotChange && isInheritanceFieldNotChange);
+        }
+
         private void SerializeConnectionInfo(ConnectionInfo connectionInfo)
         {
             _currentNodeIndex++;
-            var dataRow = _dataTable.NewRow();
-            dataRow["ID"] = DBNull.Value;
+            var isNewRow = false;
+            DataRow dataRow = _dataTable.Rows.Find(connectionInfo.ConstantID);
+            if (dataRow == null)
+            {
+                dataRow = _dataTable.NewRow();
+                dataRow["ConstantID"] = connectionInfo.ConstantID;
+                isNewRow = true;
+            }
+            else
+            {
+                sourcePrimaryKeyDict.Remove(connectionInfo.ConstantID);
+            }
+            var tmp = isRowUpdated(connectionInfo, dataRow);
+            if (!tmp){
+                return;
+            } 
             dataRow["Name"] = connectionInfo.Name;
             dataRow["Type"] = connectionInfo.GetTreeNodeType().ToString();
-            dataRow["ConstantID"] = connectionInfo.ConstantID;
             dataRow["ParentID"] = connectionInfo.Parent?.ConstantID ?? "";
             dataRow["PositionID"] = _currentNodeIndex;
             dataRow["LastChange"] = MiscTools.DBTimeStampNow();
@@ -419,8 +676,7 @@ namespace mRemoteNG.Config.Serializers.MsSql
                 dataRow["InheritRDGatewayDomain"] = false;
                 dataRow["InheritRdpVersion"] = false;
             }
-
-            _dataTable.Rows.Add(dataRow);
+            if (isNewRow)_dataTable.Rows.Add(dataRow);
         }
     }
 }
\ No newline at end of file
diff --git a/mRemoteV1/Config/Serializers/Versioning/SqlDatabaseVersionVerifier.cs b/mRemoteV1/Config/Serializers/Versioning/SqlDatabaseVersionVerifier.cs
index 40f622f6..999b7711 100644
--- a/mRemoteV1/Config/Serializers/Versioning/SqlDatabaseVersionVerifier.cs
+++ b/mRemoteV1/Config/Serializers/Versioning/SqlDatabaseVersionVerifier.cs
@@ -37,6 +37,7 @@ namespace mRemoteNG.Config.Serializers.Versioning
                     new SqlVersion24To25Upgrader(_databaseConnector),
                     new SqlVersion25To26Upgrader(_databaseConnector),
                     new SqlVersion26To27Upgrader(_databaseConnector),
+                    new SqlVersion27To28Upgrader(_databaseConnector),
                 };
 
                 foreach (var upgrader in dbUpgraders)
@@ -48,7 +49,7 @@ namespace mRemoteNG.Config.Serializers.Versioning
                 }
 
                 // DB is at the highest current supported version
-                if (databaseVersion.CompareTo(new Version(2, 7)) == 0)
+                if (databaseVersion.CompareTo(new Version(2, 8)) == 0)
                     isVerified = true;
 
                 if (isVerified == false)
diff --git a/mRemoteV1/Config/Serializers/Versioning/SqlVersion27To28Upgrader.cs b/mRemoteV1/Config/Serializers/Versioning/SqlVersion27To28Upgrader.cs
new file mode 100644
index 00000000..7f850bd8
--- /dev/null
+++ b/mRemoteV1/Config/Serializers/Versioning/SqlVersion27To28Upgrader.cs
@@ -0,0 +1,64 @@
+using mRemoteNG.App;
+using mRemoteNG.Config.DatabaseConnectors;
+using mRemoteNG.Messages;
+using System;
+using System.Data.Common;
+
+namespace mRemoteNG.Config.Serializers.Versioning
+{
+    public class SqlVersion27To28Upgrader : IVersionUpgrader
+    {
+        private readonly IDatabaseConnector _databaseConnector;
+
+        public SqlVersion27To28Upgrader(IDatabaseConnector databaseConnector)
+        {
+            _databaseConnector = databaseConnector ?? throw new ArgumentNullException(nameof(databaseConnector));
+        }
+
+        public bool CanUpgrade(Version currentVersion)
+        {
+            return currentVersion.CompareTo(new Version(2, 7)) == 0;
+        }
+
+        public Version Upgrade()
+        {
+            Runtime.MessageCollector.AddMessage(MessageClass.InformationMsg,
+                                                "Upgrading database from version 2.7 to version 2.8.");
+
+            const string mySqlText = @"
+ALTER TABLE tblCons MODIFY COLUMN ID INT;
+ALTER TABLE tblCons DROP PRIMARY KEY, ADD PRIMARY KEY (ConstantID);
+ALTER TABLE tblCons ADD INDEX `id` (ID), MODIFY ID int auto_increment;
+ALTER TABLE tblCons MODIFY COLUMN ID INT AUTO_INCREMENT, ADD UNIQUE(ID);
+UPDATE tblRoot SET ConfVersion='2.8'";
+            const string msSqlText1 = @"
+ALTER TABLE tblCons ADD  DEFAULT 0 FOR UseEnhancedMode;
+ALTER TABLE tblCons ADD  DEFAULT 0 FOR InheritUseEnhancedMode;
+UPDATE tblCons SET UseEnhancedMode = 0 WHERE UseEnhancedMode IS NULL;
+UPDATE tblCons SET InheritUseEnhancedMode = 0 WHERE InheritUseEnhancedMode IS NULL;
+ALTER TABLE tblCons ALTER COLUMN ConstantID varchar(128) NOT NULL;";
+            const string msSqlText2 = @"
+ALTER TABLE tblCons ADD CONSTRAINT PK_tblCons PRIMARY KEY (ConstantID);
+UPDATE tblRoot SET ConfVersion='2.8';";
+            DbCommand dbCommand;
+
+            if (_databaseConnector.GetType() == typeof(MSSqlDatabaseConnector))
+            {
+                dbCommand = _databaseConnector.DbCommand(msSqlText1);
+                dbCommand.ExecuteNonQuery();
+                dbCommand = _databaseConnector.DbCommand(msSqlText2);
+            } else if (_databaseConnector.GetType() == typeof(MySqlDatabaseConnector))
+            {
+                dbCommand = _databaseConnector.DbCommand(mySqlText);
+            } else
+            {
+                throw new Exception("Unknow database backend");
+            }
+
+
+
+            dbCommand.ExecuteNonQuery();
+            return new Version(2, 8);
+        }
+    }
+}
\ No newline at end of file
diff --git a/mRemoteV1/Documentation/mssql_db_setup.sql b/mRemoteV1/Documentation/mssql_db_setup.sql
index 17ec6724..b9268549 100644
--- a/mRemoteV1/Documentation/mssql_db_setup.sql
+++ b/mRemoteV1/Documentation/mssql_db_setup.sql
@@ -15,7 +15,7 @@ GO
 
 CREATE TABLE [dbo].[tblCons] (
 	ID int NOT NULL IDENTITY(1,1),
-	ConstantID varchar(128),
+	ConstantID varchar(128) NOT NULL PRIMARY KEY,
 	PositionID int NOT NULL,
 	ParentID varchar(128),
 	LastChange datetime NOT NULL,
@@ -140,11 +140,12 @@ CREATE TABLE [dbo].[tblCons] (
 	InheritRdpVersion bit DEFAULT ((0)) NOT NULL,
 	VmId varchar(100),
 	UseVmId bit,
-	UseEnhancedMode bit,
-	InheritVmId bit,
+	UseEnhancedMode bit DEFAULT ((0)),
+	InheritVmId bit ,
 	InheritUseVmId bit,
-	InheritUseEnhancedMode bit
-) GO
+	InheritUseEnhancedMode bit DEFAULT ((0))
+) ON [PRIMARY] 
+GO
 
 CREATE TABLE [dbo].[tblRoot] (
 	[Name] [varchar] (2048) NOT NULL ,
diff --git a/mRemoteV1/Documentation/mysql_db_setup.sql b/mRemoteV1/Documentation/mysql_db_setup.sql
index 545de737..be28001a 100644
--- a/mRemoteV1/Documentation/mysql_db_setup.sql
+++ b/mRemoteV1/Documentation/mysql_db_setup.sql
@@ -18,7 +18,7 @@ DROP TABLE IF EXISTS `tblCons`;
 /*!40101 SET character_set_client = utf8 */;
 CREATE TABLE `tblCons` (
     `ID` int(11) NOT NULL AUTO_INCREMENT,
-    `ConstantID` varchar(128) DEFAULT NULL,
+    `ConstantID` varchar(128) NOT NULL,
     `PositionID` int(11) NOT NULL,
     `ParentID` varchar(128) DEFAULT NULL,
     `LastChange` datetime NOT NULL,
@@ -147,7 +147,8 @@ CREATE TABLE `tblCons` (
 	`InheritVmId` tinyint(1) DEFAULT NULL,
 	`InheritUseVmId` tinyint(1) DEFAULT NULL,
 	`InheritUseEnhancedMode` tinyint(1) DEFAULT NULL,
-    PRIMARY KEY (`ID`)
+    PRIMARY KEY (`ConstantID`),
+    UNIQUE (`ID`)
 ) ENGINE=InnoDB AUTO_INCREMENT=3324 DEFAULT CHARSET=latin1;
 /*!40101 SET character_set_client = @saved_cs_client */;
     
diff --git a/mRemoteV1/Tools/MiscTools.cs b/mRemoteV1/Tools/MiscTools.cs
index e3a0899d..6d4c93f5 100644
--- a/mRemoteV1/Tools/MiscTools.cs
+++ b/mRemoteV1/Tools/MiscTools.cs
@@ -92,7 +92,7 @@ namespace mRemoteNG.Tools
 					return new MySqlDateTime(DateTime.Now);
 				case "mssql":
 				default:
-					return (SqlDateTime)DateTime.Now;
+					return DateTime.Now;
 			}
 		}
 
diff --git a/mRemoteV1/mRemoteV1.csproj b/mRemoteV1/mRemoteV1.csproj
index 4bf31d9a..5a26a6c2 100644
--- a/mRemoteV1/mRemoteV1.csproj
+++ b/mRemoteV1/mRemoteV1.csproj
@@ -208,6 +208,7 @@
     <Compile Include="Config\Serializers\Versioning\SqlVersion23To24Upgrader.cs" />
     <Compile Include="Config\Serializers\Versioning\SqlVersion24To25Upgrader.cs" />
     <Compile Include="Config\Serializers\Versioning\SqlVersion25To26Upgrader.cs" />
+    <Compile Include="Config\Serializers\Versioning\SqlVersion27To28Upgrader.cs" />
     <Compile Include="Config\Serializers\Versioning\SqlVersion26To27Upgrader.cs" />
     <Compile Include="Config\Serializers\XmlConnectionsDecryptor.cs" />
     <Compile Include="Config\DataProviders\FileDataProviderWithRollingBackup.cs" />