Fabian Zihlmann worked on the nextcloud/twofactor_gateway repository, focusing on backend development with PHP. During December 2025, Fabian delivered a targeted fix for EcallSMS compatibility, addressing a configuration error that arose after API version changes. By renaming the configuration field from 'senderid' to 'sender' and updating related method names, Fabian ensured alignment with the new EcallSMS schema and improved the system’s resilience to upgrade-time breakages. This work enhanced stability for deployments relying on sender-based configuration and reduced runtime errors during upgrades. Fabian’s contribution demonstrated depth in PHP and backend configuration management, emphasizing reliability and maintainability in production environments.