Just a side note:

Well, two

First is that I send all log files I get from the test sites just in case they might make a difference. I think one or two that turn out to be irrelevant is better than not sending the one that is.

And, because of that, I will mentiion that two upgraded sites (one with and one without OPC) will not display the details of the order (below the payment method line) without retaining the old includes/modules/payment/square_support and its files.

OTOH, several other sites work fine without that folder and files.

More info available on request. I have to break sites to get the log file for the support folder. Don't want to do that during business hours.