To upgrade an existing OPCDA.NET based application usually only the following steps are required:

1. Open the solution in Visual Studio
   
   
2. Remove the OpcDaNet.dll reference
   
   
3. In Visual Studio 2010/2012/2013/2015/2017 set the Target .Net Framework to .Net Framework 4.7.2
   
   
4. Add a reference to the OPCDA.NET V12.0 (or newer) assemblies:
   - OpcDaNetUA.Net4.dll    respectively    OpcDaNetWpfUA.Net4.dll
   - OpcNetBase.Net4.dll
   
   
5. Add a reference to the OPCDA.NET UA Option assembly
   -  OpcDaNetUaOption.Net4.dll
   in the OPCDA.NET UA Option setup directory
   
   
6. Rebuild the application. No code changes are required.
   
   
7. Use the UA Client Configuration Utility to create a default UA configuration.
   Drag the application EXE file to the utility shortcut or start the utility and browse to the application.
   In the main dialog click the  Create UA Configuration  button 
   
8. Edit the default configuration to define proper names and create a certificate for the application.
   To access remote UA servers:
   - the exported client certificate needs to be copied to the server machine and imported.
   - the exported server certificate needs to be copied from the server machine and imported.