Sorry, I'm still confused.

There are 3 separate/different 'includes' folders in the distribution and I want to make sure that I use the correct folder for the specific edits required.

So since this is an initial install on 156b, I use the unlabeled 'includes' folder and ignore the zc155f and zc156b 'includes' folders because the specific labeled 'includes' folders are ONLY used for upgrading OPC from a previous version TO the specific labeled OPC 'includes' folder?

I don't mean to be a PIA but the zc156 upgrade process has been the most confusing in my past 10 years of use and I don't want to get 2 weeks into the upgrade to find out that on day 1 the wrong file was used and require a complete do-over.