While banks keep churning out new projects, an important key to the success of any project/software is exception handling. While routine transactions generally go well executed, it is the exception handling that makes or breaks the software. While testing the software, adequate efforts should be made to prepare exhaustive test scenarios of exception and how the system handles them.
The event reminded us that, to ensure resilience, we need parallel safe infrastructures that can be scaled up, if the normal network is failing. Today, we still have cash. If or when cash is no longer used to the extent that it can be easily scaled up, other alternatives will be needed.