Banks around the world are modernizing their payment systems to address the changing demands of their customers and regulators. Real-time payments are rapidly growing in volumes. Central banks are actively exploring CBDCs. Yet how many central banks have actually modernized their systems? Many have RTGS and ACH systems designed and built decades ago, and are struggling to keep pace with developments and volumes. Furthermore, the technology was designed in a different era - making simple changes is usually a complex, costly and risky process. Central banks need to refresh their systems so that they enable even more change as they're in danger of constraining what is now possible. So what design considerations should these organisations consider as they seek to future proof as much as possible?