- Race condition in worker thread management in Lwt_unix (#569,
  diagnosed Gabe Levi).
- Hang in Lwt_unix.read on Windows (#574, #569, 86a6baf, diagnosed Gabe
  Levi).
- Docs: note that Lwt_io.open_file for writing truncates the file by
  default (#570, reported Tóth Róbert).