In December 2024, Max Zimmermann developed persistent puzzle streak functionality for the lichess-org/mobile repository, enhancing user continuity and engagement. He refactored the puzzle-loading process by migrating from loadPuzzle to onLoadPuzzle, simplifying the flow and reducing the risk of regressions. Using Flutter and Dart, Max implemented automatic streak saving after each puzzle load and introduced null-safety checks to prevent crashes when streak data is missing. His work included minor formatting improvements to the streak-saving logic, improving code readability and maintainability. The depth of the changes focused on stability and user experience, leveraging state management best practices in mobile development.