During May 2025, Rein Rijn worked on the Puma/puma repository, focusing on backend development and bug fixing using Ruby. He addressed a critical issue in the request/response pipeline by ensuring that request bodies with a nil to_path no longer caused dereference errors, thereby improving stability across HTTP/1.1 and HTTP/1.0. Rein enhanced test coverage by adding scenarios for pipe body handling, validating streaming reliability under varied client behaviors. By reading response bodies as bytes instead of characters, he resolved encoding-related issues. These targeted changes reduced production incidents and improved maintainability, demonstrating careful attention to robustness and cross-version compatibility.