diff --git a/ADDITIONS/squirrelmail-plugin/INSTALL b/ADDITIONS/squirrelmail-plugin/INSTALL
index 6a204e02..08942865 100644
--- a/ADDITIONS/squirrelmail-plugin/INSTALL
+++ b/ADDITIONS/squirrelmail-plugin/INSTALL
@@ -12,6 +12,7 @@ Requirements:
 	wget https://packages.zendframework.com/releases/ZendFramework-1.12.3/ZendFramework-1.12.3-minimal.tar.gz 
 	tar -zxf ZendFramework-1.12.3-minimal.tar.gz
 	mv ZendFramework-1.12.3-minimal/library/Zend .    )
+   NOTE: This plugin is _not compatible_ with Zend Framework version 2.x.
 
 Installation :
 ==============
diff --git a/INSTALL.TXT b/INSTALL.TXT
index a8aa83bf..c9e48d47 100644
--- a/INSTALL.TXT
+++ b/INSTALL.TXT
@@ -159,7 +159,9 @@ See ADDITIONS/squirrelmail-plugin
 See xmlrpc.php - only a subset of Postfixadmin's functionality is currently exposed.
 See config.inc.php - see xmlrpc_enabled key (defaults to off).
 
-You'll need to install a copy of the Zend Framework within Postfixadmin (see header within xmlrpc.php)
+You'll need to install a copy of the Zend Framework (version 1.12.x) within Postfixadmin
+or your PHP include_path (see header within xmlrpc.php).
+NOTE: The XMLRPC interface is _not compatible_ with Zend Framework version 2.x.
 You'll need to enable the xmlrpc link (see config.inc.php)
 
 8. More information