Clojure support upgrades to Leiningen 2.5.2
Change effective on 10 August 2015
Heroku’s support for Clojure applications has upgraded the default Leiningen version to 2.5.2. This version will be used to build your Clojure application the next time you deploy with Git. Applications configured to use Leiningen 1.x will continue to build with version 1.7.1.