If a shop has been switched from testing to production-mode and the Ingenico account was not changed, the order numbers might collide with those already saved at Ingenico. This happens if Magento starts counting the order numbers from the beginning again.

The error message will be:

"This order has already been processed"

One way to prevent this is enabling the DevPrefix in the module. Here's how to do that:

  • Edit the file app/code/community/Netresearch/OPS/etc/config.xml
  • Look for the section <devprefix></devprefix>
  • Put an arbitrary (short) prefix between the tags. Example: <devprefix>MY-PREFIX</devprefix>
  • Make sure to flush all caches (Magento, PHP, etc.) afterwards

This will put the prefix MY-PREFIX before all new order numbers that are transferred to Ingenico. Collisions with existing order numbers are therefore no longer possible. This does not change the format of the order numbers inside of Magento 

Please note:

Check if the changed number format causes problems for further payment processing or bookkeeping.