Couple of things not addressed or gone over a little lightly in either readme

This addresses UPGRADES

Up until just a couple of days ago, Square defaulted to sandbox when you entered your app. You could really get lost if you did not see that. Our current pages from Square show that they have defaulted to Production which should help. Just think the lack of sandbox for ZC should be more than line 129 in the MD

Couldn't find information in either readme regarding the changing of the API version for existing apps (some have not updated since their original creation. The latest version is 2020-03-25. The files with this new ZC version imply that this is the version needed for 1.1 to work. Version 1.0 API files listed 2020-02-26 yet nothing in the docs mentioned whether the user had to upgrade the API in square. We had several customers who were having problems that wound up being old API versions. It appears that 1.0 needed 2020-02-26. Nothing in the docs would have notified the user to change from an older version.

Since the API setting is "below the fold" on the app's landing page, it looks like most may have missed this.

Also, since the 2020-03-25 marks the start of Square's V2 of the API, I fear that only the new installs will work as most of the old installs will have an outdated API version.


BOTTOM LINE
If you are upgrading from any version prior to 1.1:
  1. (Login to https://squareup.com/dashboard/apps and click on My Apps.
  2. Click the Manage App button next to your listed App.
  3. Make sure you are in Production as Sandbox is not used with Zen Cart
  4. Scroll down to the API Version settings:
  5. For version 1.1 of this mod, make sure your Production API Version is at least version 2020-03-25 or later.
  6. .................