How to Develop a OPC DA Client in 2026|Classic OPC: DA, A&E, HDA, XML-DA, etc.|Forum|OPC Foundation

Hi, we need to develop a OPC DA client that stores data points in a timeseries DB.

During development, we got a windows virtual machine that runs the OPC DA server. Using OPC Expert, we can already see the server and read variable changes. 

So far so good, but how can we implement a client that can read the data?

What we tried so far: 

a) python 32bit with pywin32 and OpenOPC

b) Native .net 8 

Both won't work because the automation layer (opcdaauto.dll from OPC Foundation) is not present.

What is the official way to develop a client, and from where do we get the opcdaauto.dll since it is not bundled in the redistributable package download?

Thanks in advance!