diff --git a/version.h b/version.h
index 68a555cdf9..c97755b7c2 100644
--- a/version.h
+++ b/version.h
@@ -15,8 +15,8 @@
 #define RUBY_PATCHLEVEL -1
 
 #define RUBY_RELEASE_YEAR 2021
-#define RUBY_RELEASE_MONTH 8
-#define RUBY_RELEASE_DAY 31
+#define RUBY_RELEASE_MONTH 9
+#define RUBY_RELEASE_DAY 1
 
 #include "ruby/version.h"