diff --git a/man2/mprotect.2 b/man2/mprotect.2
index dd1b93076..9cc375364 100644
--- a/man2/mprotect.2
+++ b/man2/mprotect.2
@@ -135,6 +135,10 @@ in the middle of a region currently protected as
 .BR PROT_READ|PROT_WRITE
 would result in three mappings:
 two read/write mappings at each end and a read-only mapping in the middle.)
+.SH VERSIONS
+.BR pkey_mprotect ()
+first appeared in Linux 4.9.
+Glibc support is not yet available.
 .SH CONFORMING TO
 .BR mprotect ():
 POSIX.1-2001, POSIX.1-2008, SVr4.