diff --git a/ext/io/wait/io-wait.gemspec b/ext/io/wait/io-wait.gemspec
index b633421e48..7b73d64200 100644
--- a/ext/io/wait/io-wait.gemspec
+++ b/ext/io/wait/io-wait.gemspec
@@ -1,4 +1,4 @@
-_VERSION = "0.2.3"
+_VERSION = "0.3.0.pre"
 
 Gem::Specification.new do |spec|
   spec.name          = "io-wait"