We are behind and upgrading from 2.2.3. Do we need to update elasticsearch as well or can that be left alone? Are there any large or tangible benefits to doing so?
Does it not explain it in the first paragraph here?
http://docs.graylog.org/en/3.0/pages/upgrade/graylog-3.0.html
Good catch. I was going by old documentation that I had read. Hadn’t read through the latest. Thanks for the facepalm moment. 
lol