One of the benefits of Clojure is that it's Just Another JAR. If you want the to use a new version of the Java language, you have to convince your devops people

One of the benefits of Clojure is that it's Just Another JAR. If you want the to use a new version of the Java language, you have to convince your devops people to deploy a new version of the Java runtime, which may take time. If you want to use the latest version of Clojure, all you have to do is change a dependency in your build, and you can use the latest version of Clojure with Java 6 if need be. Maybe eventually compatibility with Java 6 will be abandoned, maybe eventually they'll require 8, but the Clojure devs really don't want to do that lightly.