Hopefully this can clear up some confusion. OPC is simply a communication protocol, like HTTP or RS232. It is the language Ignition speaks to communication drivers. Ignition also makes an OPC server that translates between the PLC and the OPC language.
Your version of Ignition contains an OPC server that works with Logix version 21 and lower. Since you have newer firmware versions in your PLC, the Ignition built in OPC server in 7.3 won’t work. You have a couple options:
Buy a newer version of Ignition. This will come with the newer Ignition OPC server that will communicate with the new firmware version Logix PLCs. If you have been paying a support contract that includes upgrade protection, this will be free. If not, you will have to purchase all your modules at the current price.
Back rev the Logix processor… sounds like this is not an option
Buy a third party OPC server. Kepware is a great one. This will be a separate driver that also speaks OPC - so you will stop using Ignition’s built in OPC driver and switch to a third party one. Since they both speak the same OPC protocol, the data can flow in and out of your PLC through Kepware into Ignition. This will probably be cheaper, because you won’t have to upgrade all of Ignition.
So if you decide to purchase Kepware, you will need to make sure to get the version that supports Rockwell firmware version 24. “Kepware” as a whole is a server application with many different plugins; the Kepware salespeople should be able to help you figure out what version and package you will need. Kepware support will be able to help you get Kepware installed and connected to your PLC. They or Inductive will have documentation on how to connect Ignition to Kepware; for example, there is a manual page for this specific task here: docs.inductiveautomation.com:84 … are+OPC-UA
It will be added as another OPC server same as the Ignition OPC server, and you will be able to get your data through that just like through the Ignition OPC server.
Does that make sense?