Worked on stabilizing the protocol upgrade path in the Adyen/adyen-java-api-library, focusing on secure API integration and configuration management using Java. Addressed a critical bug by reversing a previous revert to re-enable the protocol upgrade flow, introducing a protocolUpgradeEnabled flag within the configuration. This flag was integrated into the AdyenHttpClient to ensure consistent application of protocol upgrades across all requests, maintaining backward compatibility for existing clients. The changes prepared the codebase for upcoming TLS upgrade requirements, aligning with evolving security standards. The work demonstrated careful isolation of technical changes, reducing upgrade friction and supporting compliance readiness for future releases.