diff --git a/ext/io/wait/io-wait.gemspec b/ext/io/wait/io-wait.gemspec
index fc79bb4cce..ad1624585b 100644
--- a/ext/io/wait/io-wait.gemspec
+++ b/ext/io/wait/io-wait.gemspec
@@ -1,4 +1,4 @@
-_VERSION = "0.2.2"
+_VERSION = "0.2.2.pre1"
 
 Gem::Specification.new do |spec|
   spec.name          = "io-wait"