diff --git a/package.json b/package.json
index f507fed..7269846 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
     "name": "pngjs",
-    "version": "0.3.0-alpha",
+    "version": "0.4.0-alpha",
     "description": "Simple PNG encoder/decoder",
     "author": "Kuba Niegowski",
     "contributors": [],