Logstash worker parameter

Hi everybody, I am trying to tune my ELK stack, but I don't get the meaning of some parameters in logstash

I understood the PW process and main parameters of logstash, I was especially interested in thread management, but I still have one question: in a blog talking about PW and OW (here) I found that in version 2.4 you were going to remove the OW concept, has this been applied? I still find all the parameters there

Then while I was reading the doc on elastic output (the one i am using I found a value called workers (here) which meaning I don't get. it seems to me a little in contrast with PW and OW. could someone explain it better?

thanks

hey any ideas of those parameters? I really can't find anything about them