diff --git a/lib/libc/sys/vfork.2 b/lib/libc/sys/vfork.2
index e44d955c5af..a532d59522a 100644
--- a/lib/libc/sys/vfork.2
+++ b/lib/libc/sys/vfork.2
@@ -129,4 +129,4 @@ and input attempts result in an end-of-file indication.
 The
 .Fn vfork
 function call appeared in
-.Bx 3.0 .
+.Bx 2.9 .