diff --git a/version.h b/version.h
index bae9359566..fa246b226e 100644
--- a/version.h
+++ b/version.h
@@ -16,7 +16,7 @@
 
 #define RUBY_RELEASE_YEAR 2021
 #define RUBY_RELEASE_MONTH 9
-#define RUBY_RELEASE_DAY 9
+#define RUBY_RELEASE_DAY 10
 
 #include "ruby/version.h"