Additions

• ?suffix argument for Lwt_io.with_temp_file and Lwt_io.open_temp_file (#724, requested Volker Diels-Grabsch).
• Lwt_io.with_temp_dir and Lwt_io.create_temp_dir (#724, requested Volker Diels-Grabsch).

Changes

• Lwt_io.establish_server: increase default backlog from 5 to SOMAXCONN (#731, suggested Konstantin Olkhovskiy).
• PPX: use OCaml 4.09 ASTs to support recent features (074f679).
• PPX: deprecate let%lwt structure items (#733, prompted Didier Le Botlan).

Miscellaneous

• Tests now pass in more environments (#721, #722, #725, #729, reported Olaf Hering).