<?xml version="1.0"?> <configuration xmlns:xdt="http://schemas.microsoft.com/XML-Document-Transform"> <connectionStrings> <add name="PGSheetControlEntities" connectionString="metadata=res://*/PGSheetModel.csdl|res://*/PGSheetModel.ssdl|res://*/PGSheetModel.msl;provider=System.Data.SqlClient;provider connection string="Data Source=192.168.0.15;Initial Catalog=PGSheetControl;User ID=sa;Password=xxxxx ;MultipleActiveResultSets=True"" providerName="System.Data.EntityClient" xdt:Transform="Replace" xdt:Locator="Match(name)"/> </connectionStrings> </configuration>i.e. copy the default entry for the 'add' attribute, change the Data Source (and any other parameters that are different and add the xdt:Transform attribute. You can right click on the release config and use 'Preview Transform' to confirm that everything is correct.