Most projects will need:

• “OPC Labs Base Library Core” (OpcLabs.BaseLib.dll)
• for OPC Classic: “OPC Labs EasyOPC “Classic” Library” (OpcLabs.EasyOpcClassic.dll)
• for OPC UA: “EasyOPC-UA Library” (OpcLabs.EasyOpcUA.dll)

Some project will also need other assemblies, such as

• "OPC Labs Base Library Forms" (OpcLabs.BaseLibForms.dll) (not in .NET Standard)
• "OPC Labs Base Library Presentation" (OpcLabs.BaseLibPresentation.dll) (not in .NET Standard)
• “OPC Labs EasyOPC Forms” (OpcLabs.EasyOpcForms.dll) (not in .NET Standard)
• “OPC Labs EasyOPC Presentation” (OpcLabs.EasyOpcPresentation.dll) (not in .NET Standard)

You do not need to (and should not) ever reference the following assemblies:

• "OPC Labs DotProlog" (OpcLabs.DotProlog.dll)
• EasyOPC “Classic” Raw Library (x64) (App_Web_OpcLabs.EasyOpcClassicRaw.amd64.dll)
• EasyOPC “Classic” Raw Library (x86) (App_Web_OpcLabs.EasyOpcClassicRaw.x86.dll)

This does not mean that these assemblies are useless or are not used. They are used indirectly, by the relevant assemblies that you do reference, and they will copied over to the target automatically by the build tools.

In OPC UA PubSub, if you want to work with raw Ethernet packet mappings, or Wireshark capture files, the OpcLabc.Pcap assembly must be made available to your program - usually you achieve it by referencing this assembly, although it is not directly used by your code.