Valeref developed cross-device call decline handling for the element-hq/element-x-ios repository, enabling calls declined on one device to stop ringing across all connected devices. This feature was implemented using Swift and iOS development skills, leveraging real-time communication techniques to synchronize call state through event listeners and propagation logic. Valeref also performed code cleanup and aligned naming conventions to improve maintainability and ease onboarding for future contributors. The work addressed user confusion by ensuring a consistent multi-device experience and reduced potential support issues. The depth of the solution established a robust foundation for future cross-device features within the mobile application.