Test a Hugo 0.165 upgrade in an isolated destination before replacing the site build
A Hugo upgrade is easy to mistake for a binary replacement. The risk is usually not the executable itself. It is the contract between the executable, the site configuration, the theme, asset transforms, and the directory that receives generated files. A build that succeeds in a throwaway directory can expose a compatibility problem without overwriting the deployment artifact or hiding an unrelated generated change.
Hugo v0.165.0 was released on 12 August 2026. Its release notes add css.ChromaStyles and an importContext option for CSS, JavaScript, Sass, and PostCSS transforms. They also remove tailwindcss from the default security.exec.allow list. That last change is a useful reminder that a theme can depend on an external build tool even when the site repository has no obvious application package manifest.