Yes :) I'm looking for the set of versions that are the latest that will play nice with the latest version 2.x version of elasticsearch. Yes, I eventually plan to upgrade to 5.5.x or whatever is latest at that time but not looking to do that work now.
A bit more background. I'm using the elastic stack for monitoring only - both logs and server metrics. I also need to "productionize" the architecture - I currently have just two nodes running elasticsearch. One of those is also running logstash (which is configured to talk to both) AND kibana. We're also running on that same server a locally written app similar to Watcher which queries ES and does alerting.