diff --git a/lib/gnuplotrb/version.rb b/lib/gnuplotrb/version.rb
index c1e9533..277b88b 100644
--- a/lib/gnuplotrb/version.rb
+++ b/lib/gnuplotrb/version.rb
@@ -4,5 +4,5 @@
 module GnuplotRB
   ##
   # Gem version
-  VERSION = '0.3.4'
+  VERSION = '0.4.0'.freeze
 end