diff --git a/lib/libc/string/ffs.3 b/lib/libc/string/ffs.3
index e66d7eb1e5f3..acb1ac88b7cd 100644
--- a/lib/libc/string/ffs.3
+++ b/lib/libc/string/ffs.3
@@ -108,4 +108,4 @@ The
 and
 .Fn flsll
 functions appeared in
-.Fx 8.0 .
+.Fx 7.1 .