1.5.3

This is a second update to security release 1.5.1, addressing the potential for multiple client charges due to improper handling of exceptions in the completetransaction call. It also includes a fix to allow administrators other than the super user to see the iATS console page. Both of these bugs were also present in 1.5.0.

The original 1.5.1 release was a security release documented here: https://github.com/iATSPayments/com.iatspayments.civicrm/releases/tag/1.5.2