Worked on improving file upload reliability in the nextcloud/talk-android repository, focusing on resolving a bug that caused attachments to fail appearing in conversations. Addressed this by enhancing the upload pipeline, including raising the chunked upload threshold to optimize file handling and introducing retry logic for share creation to better manage large files and network inconsistencies. Refactored upload components to ensure accurate filecache updates and robust HTTP response handling, reducing user-facing errors. Utilized Kotlin for Android development, leveraging API integration and file upload management skills to deliver a more stable messaging experience for mobile users collaborating through the application.