I’ve upgraded to new version of twig/twig 3.x.x. As of twig version 3.0 Twig_Extension is deprecated. So I’m getting next with "whiteoctober/breadcrumbs-bundle"
!! In BreadcrumbsExtension.php line 12: !! !! Attempted to load class "Twig_Extension" from the global namespace. !! Did you forget a "use" statement?
Any suggestion how to fix this?
Source: Symfony4 Questions