I upgraded from 5.6.3 to 6.0 and i have two question:
- Need upgrade all beat to 6.0 ? v5.6.x conflict with ES 6.0.0?
 - I got %{[@metadata][beat]}-%{[@metadata][version]}-2017-37 in index name.
Flow data : beat -> LS forwarder -> RabbitMQ -> LS Proccessor -> ES. 
Config in LS forwarder
input {
  beats {
    port => 5044
  }
}
filter {
  if [type] == "wineventlog" and [event_id] == 5156 {
    drop { }
  }
  mutate {
   add_field => {"beatname" => "%{[@metadata][beat]}"}
   add_field => {"beattype" => "%{[@metadata][type]}"}
   add_field => {"beatversion" => "%{[@metadata][version]}"}
  }
}
output {
    rabbitmq {
        exchange => "logstash"
        exchange_type => "direct"
        key => "logstash-key"
        host => "10.1.100.10"
        vhost => "elastic-stack"
        durable => true
        persistent => true
        port => 5677
        user => "logstash"
        password => "password"
    }
}
Confing LS Proccessor
input {
    rabbitmq {
        host => "10.1.100.10"
        queue => "logstash-queue"
        key => "logstash-key"
        exchange => "logstash"
        threads => 5
        exclusive => false
        prefetch_count => 256
        vhost => "elastic-stack"
        port => 5677
        user => "logstash"
        password => "password"
    }
}
output {
    elasticsearch {
        hosts => ["http://node1:9200", "node2:9200", "node3:9200"]
        user => "user"
        password => "passs"
        manage_template => false
        index => "%{beatname}-%{beatversion}-%{+xxxx.ww}"
        #index => "%{[@metadata][beat]}-%{[@metadata][version]}-%{+xxxx.ww}"
        document_type => "%{beattype}"
    }
}
Somehing wrong in my config? . This config is worked with 5.6.x. i just add more field beatversion for 6.0