$ clj -Sdeps '{:deps {org.clojure/clojure {:mvn/version "1.8.0"}}}'
Clojure 1.8.0
user=> (let [2])
IllegalArgumentException let requires an even number of forms in binding vector in user:1 clojure.core/let (core.clj:4333)
$ clj -Sdeps '{:deps {org.clojure/clojure {:mvn/version "1.9.0"}}}'