What's new since version 8.37.0?

Major new features

• Improved support for responsive images — Added support for pixel density (DPR) for responsive images (allows optimization of srcset for high-density screens).
• Ability to override robots.txt — Ability to create a pages/robots.md page to replace the default robots.txt. Useful for managing indexing exclusions per project.
• Improved post-processing — Continued use of extension/post-processor capabilities (inherited from the 8.x branch) to enable final output processing.

Improvements & usability

• Simplified configuration structure — Options are easier to disable (option: false or option: enabled: false); automatic import of theme configurations via setConfig() / setSourceDir().
• Redesigned/enhanced cache — New, more robust cache mechanism (automatic rebuilding when files change), at the cost of a slight performance hit in some cases.
• Improved error message handling and display — Error messages are clearer to facilitate debugging.

Major fixes

• Updated remote asset management — Remote assets are better managed (caching, fallback, etc.).
• Fixes for templates and filters — Cleanup of deprecated elements/those left in the documentation (following the 8.0 → 8.x migration) and various fixes related to asset/template rendering.

Breaking changes & points of attention

• Removal of default taxonomies — tag and category are no longer created automatically: if you were using these taxonomies, you must declare them explicitly in the taxonomies: configuration. There is a risk of broken pages if you update without adapting the configuration.
• Renaming/moving options — Several options have been renamed or moved (e.g., pagination → pages:pagination, paths → pages:paths, remote_fallback → fallback, force_slash → leading_slash).
• Check custom templates — Some deprecated Twig files and filters were removed in the 8.x updates; you should review and update your custom templates.

Recommended actions for migration

1. Explicitly add taxonomies: if you plan to use tags/category.
2. Check and adapt the renamed options (pagination, paths, assets fallback, leading_slash).
3. Test the complete build and verify the cache/remote assets.
4. Review the Twig templates (deprecated functions/filters) and take advantage of new features (DPR/pixel density in images).