C-Kermit 11 Revives a 45-Year-Old File-Transfer Workhorse After 15 Years

Kermit, the cross-platform serial file-transfer protocol Frank da Cruz and Bill Catchings built at Columbia University in 1981, has a new flagship release — the first full C-Kermit version since 2011. Designed in an era when machines from different vendors often couldn’t talk to each other, Kermit handled character-set translation, 8-bit-over-7-bit links, and unreliable serial connections, and it never really went away: it still moves firmware to embedded devices, links vintage hardware, and served aboard the ISS. New maintainer John Goerzen, who packages Kermit for Debian, took over active development after da Cruz’s 2025 retirement and shipped C-Kermit 11 in July 2026.

The work amounts to a serious modernization of a decades-old C codebase that still targets VMS, OS/2, and pre-ANSI compilers. Goerzen hardened memory safety, added protections against a malicious remote peer (echoing fixes scp received years ago), and changed defaults away from legacy character-set and line-ending conversion that had occasionally corrupted binary transfers. He also added conditionally-compiled IPv6 support, roughly 2,000 unit and end-to-end test cases that surfaced bugs going back decades, and CI covering Linux (x86_64/arm64), macOS, and the BSDs. Because the project historically used no version control, he pruned large amounts of dead #ifdef COMMENT code — leaving C-Kermit with fewer lines than before.

The release also marks a governance shift. The patch volume outgrew what made sense as a Debian-specific series, so Goerzen launched Open Kermit to coordinate future development in the open. C-Kermit 11 is dedicated to da Cruz, who stayed personally involved with the project for 44 years — an unusually long tenure for an open-source founder — and it stands as a reminder that these quiet interoperability tools remain load-bearing infrastructure.