Hi Chouby, I’ve tried to add it, but nothing changed. The feed url was stil broken (not adding the language in the url), and disabling the https plugin (having it forced by htaccess everywhere) everything broke with the language not added in the posts and pages links anymore. Even with that define in the config.
Once I removed the htaccess line (and loaded under http insted of https) everything went back working. I cannot find a way of having this plugin under https working