diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7aa2118..51cf9f5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,8 @@
+2.3.1
+-------
+
+- Fix #67 a y chars will invalid error (only in 2.3.0).
+
 2.3.0
 -------
 
diff --git a/Gemfile.lock b/Gemfile.lock
index 1ec1a17..3646f8c 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    rucaptcha (2.3.0)
+    rucaptcha (2.3.1)
       railties (>= 3.2)
 
 GEM
diff --git a/lib/rucaptcha/version.rb b/lib/rucaptcha/version.rb
index c4947cc..ac6c77f 100644
--- a/lib/rucaptcha/version.rb
+++ b/lib/rucaptcha/version.rb
@@ -1,3 +1,3 @@
 module RuCaptcha
-  VERSION = '2.3.0'
+  VERSION = '2.3.1'
 end