What do we need to do to make this compatible with ElasticSearch 2+

At present we have only tested this with version 1.7.2.
When we attempt to update the version to 2.1.0 in the Vagrantfile the server is unavailable.
The default version on Travis-CI is 1.4.0 see: https://travis-ci.org/dwyl/esta/builds/95443871#L174
So we need to figure out how to bump that up in the .travis.yml first...
Any help would be much appreciated.