diff --git a/project.clj b/project.clj
index 0d3afbd..d01a333 100644
--- a/project.clj
+++ b/project.clj
@@ -1,4 +1,4 @@
-(defproject wavejumper/boonmee "0.1.0-alpha1"
+(defproject wavejumper/boonmee "0.1.0-alpha2"
   :description "cljs tooling"
   :url "https://github.com/wavejumper/boonmee"
 
diff --git a/src/boonmee/util.clj b/src/boonmee/util.clj
index b19225e..879ec26 100644
--- a/src/boonmee/util.clj
+++ b/src/boonmee/util.clj
@@ -30,7 +30,7 @@
      (-line-handler r# f#)))
 
 (defn sha256
-  [string]
+  [^String string]
   (let [digest (.digest (MessageDigest/getInstance "SHA-256") (.getBytes string "UTF-8"))]
     (apply str (map (partial format "%02x") digest))))