`ubuntu-latest` rolls to Ubuntu 26.04 between October 19 and November 19, 2026, and the change is gradual.
The default Python moves from 3.12.3 to 3.14.4, Node.js from 22.23.2 to 24.21.0, and Java from 17 to 25.
Setup actions such as `actions/setup-node` and `actions/setup-python` are unaffected, because both images cache the same versions.