Worked on stabilizing the CodecRegistry component within the xmtp/xmtp-ios repository, focusing on enhancing thread safety and reliability for concurrent codec access in an iOS application. Addressed a race condition by introducing an NSLock to protect the shared codecs dictionary and refactored CodecRegistry into a dedicated class with synchronized access and modification methods. This approach improved the predictability and stability of codec operations across multi-threaded environments, laying the foundation for future concurrency improvements. Utilized Swift and applied principles of concurrency and software design to ensure maintainable code paths, with minimal impact on user-facing functionality while resolving a critical bug.