monolog:
    channels: [deprecation]
    handlers:
        main:
            type: stream
            path: "php://stdout"
            level: info
            channels: ["!deprecation", "!event"]
        file:
            type: stream
            path: "%kernel.logs_dir%/%kernel.environment%.log"
            level: debug
            channels: ["!event"] # Include deprecations only in local, file-based logs.
        # uncomment to get logging in your browser
        # you may have to allow bigger header sizes in your Web server configuration
        #firephp:
        #    type: firephp
        #    level: info
        #chromephp:
        #    type: chromephp
        #    level: info
        console:
            type: console
            process_psr_3_messages: false
            channels: ["!console", "!deprecation", "!doctrine", "!event"]

monolog:
    channels: [deprecation]
    handlers:
        main:
            type: fingers_crossed
            handler: stream
            level: info
            buffer_size: 50 # How many messages should be saved? Prevent memory leaks
            channels: ["!deprecation"]
            excluded_http_codes: [404]
        stream:
            type: stream
            path: "php://stdout"
        file:
            type: stream
            path: "%kernel.logs_dir%/%kernel.environment%.log"
            level: debug
            channels: ["!event"] # Include deprecations only in local, file-based logs.
        # uncomment to get logging in your browser
        # you may have to allow bigger header sizes in your Web server configuration
        #firephp:
        #    type: firephp
        #    level: info
        #chromephp:
        #    type: chromephp
        #    level: info
        console:
            type: console
            process_psr_3_messages: false
            channels: ["!console", "!deprecation", "!doctrine", "!event"]

Fix old Monolog `excluded_http_codes` approach
Fix old Monolog `excluded_http_codes` approach

See also https://github.com/outlandishideas/wpackagist/pull/455
