Changelog

1.2.4

Fix KeyError during per-locale builds on Sphinx 9. Sphinx 9 normalizes the language config to the hyphenated BCP-47 form (e.g. de-DE) before passing it to the Jinja template context, but the theme's languages dict is keyed in the underscored form that Crowdin's locale strings are rewritten to at load time. get_language_code / get_language_display_name now accept either form and fall back to the underscored variant, so the versions.html template renders cleanly under Sphinx 7, 8, and 9.

Register translations.js via builder.add_js_file() instead of appending to builder.script_files. In Sphinx 7+, script_files contains JavaScript objects rather than strings, so the old duplicate-guard check no longer matched and caused the file to be re-appended on every build.

Bump install_requires ceiling to sphinx>=4.5,<10 so the theme installs alongside Sphinx 9.x. No template, CSS, or Python API changes — verified by running a full SpongeDocs build with -W against Sphinx 9.1.0.

Bump install_requires to sphinx-rtd-theme>=2.0,<4 and sphinx>=4.5,<9 so the theme installs alongside modern Sphinx (5.x / 6.x / 7.x). sphinx-rtd-theme 1.0 pinned docutils<0.18, which blocked SpongeDocs from upgrading past Sphinx 4.5.
No template or CSS changes. The RTD-theme 2.x/3.x class names this theme hooks into (wy-*, rst-versions, rst-current-version, rst-other-versions, rst-footer-buttons, headerlink) and the overridden block (sidebartitle) are unchanged in the target versions.

See Git history.