We have been made aware of an issue by Secure Trading and a customer on how existing iPayment versions handle settlements on existing authorisation when using Secure Trading as the gateway.
The issue is that instead of updating the existing authorisation to "Settled" iPayment will instead suspend the authorisation and create a new settlement with the authorisation as the parent. This works and the customer will get billed the correct amount.
The issue with this approach has been identified by Secure Trading as leading to reserving an unneeded amount of money on the customers Credit card as both the auth and the settlement will reserve the money on the Credit Card. The auth will automatically expire but the correct approach would be to update the existing authorisation and settle it directly instead of using it as a parent transaction.
All version prior to 2016.1.0 are affected by this and we recommend upgrading to 2016.1.0.