diff --git a/lib/concurrent/version.rb b/lib/concurrent/version.rb
index c698acacb..6398c620e 100644
--- a/lib/concurrent/version.rb
+++ b/lib/concurrent/version.rb
@@ -1,3 +1,3 @@
 module Concurrent
-  VERSION = '0.3.2'
+  VERSION = '0.4.0'
 end