diff --git a/auth/cas/auth.php b/auth/cas/auth.php
index 193c83df708..c8f3faae906 100644
--- a/auth/cas/auth.php
+++ b/auth/cas/auth.php
@@ -274,8 +274,8 @@ class auth_plugin_cas extends auth_plugin_ldap {
         if (!isset($config->bind_pw)) {
             $config->bind_pw = '';
         }
-        if (!isset($config->ldapversion)) {
-            $config->ldapversion = '3';
+        if (!isset($config->ldap_version)) {
+            $config->ldap_version = '3';
         }
         if (!isset($config->objectclass)) {
             $config->objectclass = '';
@@ -317,7 +317,7 @@ class auth_plugin_cas extends auth_plugin_ldap {
         set_config('opt_deref', $config->opt_deref, $this->pluginconfig);
         set_config('bind_dn', trim($config->bind_dn), $this->pluginconfig);
         set_config('bind_pw', $config->bind_pw, $this->pluginconfig);
-        set_config('ldapversion', $config->ldapversion, $this->pluginconfig);
+        set_config('ldap_version', $config->ldap_version, $this->pluginconfig);
         set_config('objectclass', trim($config->objectclass), $this->pluginconfig);
         set_config('memberattribute', moodle_strtolower(trim($config->memberattribute)), $this->pluginconfig);
         set_config('memberattribute_isdn', $config->memberattribute_isdn, $this->pluginconfig);
diff --git a/auth/cas/config.html b/auth/cas/config.html
index 13c38c77dcd..de6595b66ca 100644
--- a/auth/cas/config.html
+++ b/auth/cas/config.html
@@ -56,8 +56,8 @@ if (!isset($config->bind_dn)) {
 if (!isset($config->bind_pw)) {
     $config->bind_pw = '';
 }
-if (!isset($config->ldapversion)) {
-    $config->ldapversion = '3';
+if (!isset($config->ldap_version)) {
+    $config->ldap_version = '3';
 }
 if (!isset($config->objectclass)) {
     $config->objectclass = '';
@@ -200,8 +200,8 @@ $yesno = array( get_string('no'), get_string('yes') );
              $versions = array();
              $versions[2] = '2';
              $versions[3] = '3';
-             echo html_writer::select($versions, 'ldapversion', $config->ldapversion, false);
-             if (isset($err['ldapversion'])) { echo $OUTPUT->error_text($err['ldapversion']); }
+             echo html_writer::select($versions, 'ldap_version', $config->ldap_version, false);
+             if (isset($err['ldap_version'])) { echo $OUTPUT->error_text($err['ldap_version']); }
         ?>
     </td>
     <td>