diff --git a/version.h b/version.h
index 62104bcb11..f6cbdc5c24 100644
--- a/version.h
+++ b/version.h
@@ -4,7 +4,7 @@
 
 #define RUBY_RELEASE_YEAR 2018
 #define RUBY_RELEASE_MONTH 1
-#define RUBY_RELEASE_DAY 30
+#define RUBY_RELEASE_DAY 31
 
 #include "ruby/version.h"