How do I operate on my core without disrupting the bank?

A bank's core system cannot be shut down, so modernization is done while the system is running. This involves a phased approach: optimizing online and batch processes, upgrading to COBOL 6, and optimizing connections. host to host, Expose functions through APIs to decouple channels and, using the strangler pattern, replace components without turning off the rest.

Each step is accompanied by continuous testing and plans to backtrack if something goes wrong. In this episode of our “Off the Record” series, we talk with Pablo Reitano, Head of Modernization & Legacy at IT Patagonia on these points:

• It is modernized while the system is running: optimization, APIs and gradual replacement (strangler), what does this imply?
• The conditions for success are execution: turnkey, key people involved, and a clear scope.
• Systematic monitoring of benefits and progress reports support the program.
• Internal resistance is a factor that must be managed from the beginning.

Where these programs usually fail

The biggest risk is rarely technology. The critical issues that recur in large-scale programs are continuous executive alignment and decision-making agility in committees, the availability of key bank teams for surveys, testing, and training, systematic monitoring of benefits, scope control, and careful allocation of hours, which are often very tight.

Three conditions of execution

Turnkey: a comprehensive program with a single person responsible for the outcome and governed jointly, in which people are involved from the beginning: the financial entity's technical teams participate in surveys, tests and training, and mainframe architects talk with open platform architects.

Clear scope: anything that appears outside the original plan is managed as a separate project, so as not to overwhelm the program.

The political aspect of change

Modernize the core It also has a human and political component. There are teams that have been with the system for decades and don't always want to change it. That's why shared governance and constant communication aren't extras: they're part of the plan, just like the metrics that show progress.