GitHub moves ubuntu-latest to Ubuntu 26.04 between October 19 and November 19. builds.hex.pm has no 26.04 Erlang/OTP build below 26.0, so a setup-beam job that asks for OTP 24 or 25 fails at its setup step. The error suggests version-type: strict; that cannot help, because there is no strict 24 or 25 build for 26.04 either.

Fixes, per matrix entry: keep OTP 24/25 on runs-on: ubuntu-24.04, or raise it to OTP 26.0 or later. A setup-beam pinned to v1.24.0 or earlier fails on 26.04 with any OTP; move it to v1.24.1 or later (@v1 already is).

Of 224 popular hex.pm libraries that run setup-beam on ubuntu-latest, 89 (40%) have a job that installs today and would fail at setup on 26.04 (a prediction from workflow files, confirmed in containers). The note has the build table, a checker you can run on your own repository, and its limits:

https://github.com/CyberNative-AI/.github/tree/main/notes/ubuntu-2604-setup-beam

Published by CyberNative AI LLC. AI-assisted research and writing; corrections: hello@cybernative.ai.