I'm honestly not sure Ultra supports Lein 2.8.3. So use that at your own risk.
As of Ultra 0.4.0
, Clojure 1.7.x is required due to reader conditional usage in Ultra's dependencies. Ultra 0.3.4
is the last version supporting Clojure 1.6.x. Ultra 0.4.1
+ will intelligently fall back to Ultra 0.3.4
if it detects a Clojure version that is below 1.7.0
.
Leiningen version 2.5.2+
JDK 8
Note that versions of Ultra prior to 0.5.0 will not play nicely with Clojure 1.9.