After 15 Years, C-Kermit Returns — The 45-Year-Old Protocol That Refuses to Die

John Goerzen ships C-Kermit 11, the first new release in 15 years of the protocol that once linked everything from the International Space Station to pocket calculators — now with IPv6, modern CI, and nearly 2,000 test cases.

Forty-five years after Frank da Cruz and Bill Catchings designed Kermit at Columbia University to bridge the gap between incompatible mainframes, the venerable file-transfer protocol has received its first stable release in a decade and a half. C-Kermit 11, shipped today by Debian maintainer and long-time Kermit advocate John Goerzen, brings IPv6 support, memory-safety hardening, and a modern CI pipeline that runs nearly 2,000 tests across Linux, macOS, FreeBSD, NetBSD, and OpenBSD — a far cry from the protocol's origins on 1980s serial links.

Kermit's reach over the decades has been quietly remarkable. It has flown on the International Space Station, collected data from hurricane sensors, transmitted firmware updates to embedded radios, and even processed Boeing 787 manufacturing data. Goerzen himself still uses it as a powerful SSH wrapper, an HP-48GX calculator bridge, and a BBS client. "I find that the easiest way to get large files between two computers is to spin up Kermit," he writes.

The release is dedicated to Frank da Cruz, who remained directly involved with Kermit for 44 years — from its initial design in 1981 through his retirement in 2025. Goerzen notes he knows of no other open-source project where a founder stayed so personally engaged for so long: Richard Stallman started GNU Emacs three years after Kermit but stepped back around 2008. The project now lives on under the Open Kermit banner, with binary releases available for every major platform.

Working with a decades-old C codebase — one that still conditionally builds on VMS and OS/2 alongside modern systems — proved unexpectedly rewarding. "I've been living in the C-Kermit codebase for a few months now, and I enjoy it," Goerzen writes. Alongside the infrastructure overhaul, he fixed security issues, resolved bugs that had lingered for decades, and added compatibility tests against the embedded gkermit and ekermit implementations. C-Kermit development had never used version control, so part of the work involved importing historical releases into Git.

In an era where protocols come and go in months, Kermit's endurance is a reminder that some infrastructure is built to last — even if it takes 15 years between releases.