you need to upgrade to a minimum of OPC 2.4.0. see:
https://github.com/lat9/one_page_che...ses/tag/v2.4.0
which will require a move to zc 157a.
once there, on the admin, you can got to:
configuration -> One-Page Checkout Settings -> Payment Methods Handling Form Submittal
and then esnure that square_webPay is listed there.
best.
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