Elasticsearch 1.0.0 was released less than 2 years ago. A project with more than 100 M$ of funding may be able to maintain stable branches for users who cannot

Elasticsearch 1.0.0 was released less than 2 years ago. A project with more than 100 M$ of funding may be able to maintain stable branches for users who cannot cope with the non-trivial upgrades to more recent versions.