diff --git a/README b/README
index c8e1b518..32af9359 100644
--- a/README
+++ b/README
@@ -3,7 +3,7 @@ image:https://travis-ci.org/Yubico/yubico-pam.svg?branch=master["Build Status",
 
 The Yubico PAM module provides an easy way to integrate the YubiKey
 into your existing user authentication infrastructure. PAM is used by
-GNU/Linux, Solaris and Mac OS X for user authentication, and by other
+GNU/Linux, Solaris and Mac OS X (up to 10.13) for user authentication, and by other
 specialized applications such as NCSA MyProxy.
 
 Status and Roadmap
diff --git a/doc/MacOS_X_Challenge-Response.adoc b/doc/MacOS_X_Challenge-Response.adoc
index eb911a87..5fe04953 100644
--- a/doc/MacOS_X_Challenge-Response.adoc
+++ b/doc/MacOS_X_Challenge-Response.adoc
@@ -1,14 +1,12 @@
 == Setting up your YubiKey for challenge response authentication on Max OS X ==
 
 This article explains the process to get the challenge-response
-authentication possible with newer YubiKeys working on Mac OS X. Since
-Mac OS X uses PAM like most other Unix/POSIX systems do, most of this
-should apply to other operating systems, too.
+authentication possible with newer YubiKeys working on Mac OS X up to 10.13. Starting from 10.14, Mac OS no longer supports PAM. However, these steps may be used in other UNIX/POSIX systems which support PAM.
 
 === Getting yubico-pam ===
 
 First you will have to install yubico-pam and its dependencies
-required for challenge-response authentication. Use your
+required for challenge-response authentication. Note that PAM does not work on Mac OS 10.14 or above. Use your
 distribution's package manager to get it, or build from source. If
 you're on OS X you can use http://www.macports.org[MacPorts] to
 install yubico-pam: