In the Upgrading documentation page, there is a line that needs to be fixed:

In ezpublish/config/config.yml, you need to add a few default values for the framework

framework:
    router:
        strict_requirements: %kernel.debug%
    trusted_proxies: ~    
    http_method_override: true

In the default ezpublish/config/config.yml, file, the line comes this way

router:          { resource: "%kernel.root_dir%/config/routing.yml" }

And the example should be displayed in this way:

framework:
    router:          
        resource: "%kernel.root_dir%/config/routing.yml"
        strict_requirements: %kernel.debug%
    trusted_proxies: ~    
    http_method_override: true