diff --git a/lib/libc/gen/readpassphrase.3 b/lib/libc/gen/readpassphrase.3
index 3bcee6f5638d..174639263997 100644
--- a/lib/libc/gen/readpassphrase.3
+++ b/lib/libc/gen/readpassphrase.3
@@ -178,4 +178,6 @@ extension and should not be used if portability is desired.
 The
 .Fn readpassphrase
 function first appeared in
+.Fx 4.6
+and
 .Ox 2.9 .