diff --git a/admin/settings/competency.php b/admin/settings/competency.php
index 1fffa73271e..379895355c7 100644
--- a/admin/settings/competency.php
+++ b/admin/settings/competency.php
@@ -30,17 +30,15 @@ if (has_capability('moodle/site:config', $systemcontext)) {
     $parentname = 'competencies';
 
     // Settings page.
+    $iscompetencyenabled = get_config('core_competency', 'enabled');
     $settings = new admin_settingpage('competencysettings', new lang_string('competenciessettings', 'core_competency'),
-        'moodle/site:config', false);
-    $ADMIN->add($parentname, $settings);
+    'moodle/site:config', !$iscompetencyenabled);
+    if ($iscompetencyenabled) {
+        $ADMIN->add($parentname, $settings);
+    }
 
     // Load the full tree of settings.
     if ($ADMIN->fulltree) {
-        $setting = new admin_setting_configcheckbox('core_competency/enabled',
-            new lang_string('enablecompetencies', 'core_competency'),
-            new lang_string('enablecompetencies_desc', 'core_competency'), 1);
-        $settings->add($setting);
-
         $setting = new admin_setting_configcheckbox('core_competency/pushcourseratingstouserplans',
             new lang_string('pushcourseratingstouserplans', 'core_competency'),
             new lang_string('pushcourseratingstouserplans_desc', 'core_competency'), 1);
diff --git a/admin/settings/messaging.php b/admin/settings/messaging.php
index 2221e72a5ae..9248a26f7fd 100644
--- a/admin/settings/messaging.php
+++ b/admin/settings/messaging.php
@@ -24,11 +24,12 @@
 defined('MOODLE_INTERNAL') || die();
 
 if ($hassiteconfig) {
-    $temp = new admin_settingpage('messages', new lang_string('messagingssettings', 'admin'));
-    $temp->add(new admin_setting_configcheckbox('messaging',
-        new lang_string('messaging', 'admin'),
-        new lang_string('configmessaging', 'admin'),
-        1));
+    $temp = new admin_settingpage('messages',
+        new lang_string('messagingssettings', 'admin'),
+        'moodle/site:config',
+        !$CFG->messaging
+    );
+
     $temp->add(new admin_setting_configcheckbox('messagingallusers',
             new lang_string('messagingallusers', 'admin'),
             new lang_string('configmessagingallusers', 'admin'),
diff --git a/admin/settings/subsystems.php b/admin/settings/subsystems.php
index 01de61c3e36..10e06c639e9 100644
--- a/admin/settings/subsystems.php
+++ b/admin/settings/subsystems.php
@@ -52,6 +52,18 @@ if ($hassiteconfig) { // speedup for non-admins, add all caps used on this page
     $optionalsubsystems->add(new admin_setting_configcheckbox('enableanalytics', new lang_string('enableanalytics', 'admin'),
         new lang_string('configenableanalytics', 'admin'), 1, 1, 0));
 
+    $optionalsubsystems->add(new admin_setting_configcheckbox('core_competency/enabled',
+        new lang_string('enablecompetencies', 'core_competency'),
+        new lang_string('enablecompetencies_desc', 'core_competency'),
+        1)
+    );
+
+    $optionalsubsystems->add(new admin_setting_configcheckbox('messaging',
+        new lang_string('messaging', 'admin'),
+        new lang_string('configmessaging', 'admin'),
+        1)
+    );
+
     $fullunicodesupport = true;
     if ($DB->get_dbfamily() == 'mysql') {
         $collation = $DB->get_dbcollation();
diff --git a/admin/tool/lpimportcsv/settings.php b/admin/tool/lpimportcsv/settings.php
index 8cc12da850d..c9c32c8360a 100644
--- a/admin/tool/lpimportcsv/settings.php
+++ b/admin/tool/lpimportcsv/settings.php
@@ -25,22 +25,24 @@
  */
 defined('MOODLE_INTERNAL') || die;
 
-// Manage competency frameworks page.
-$temp = new admin_externalpage(
-    'toollpimportcsv',
-    get_string('pluginname', 'tool_lpimportcsv'),
-    new moodle_url('/admin/tool/lpimportcsv/index.php'),
-    'moodle/competency:competencymanage'
-);
-$ADMIN->add('competencies', $temp);
-// Export competency framework page.
-$temp = new admin_externalpage(
-    'toollpexportcsv',
-    get_string('exportnavlink', 'tool_lpimportcsv'),
-    new moodle_url('/admin/tool/lpimportcsv/export.php'),
-    'moodle/competency:competencymanage'
-);
-$ADMIN->add('competencies', $temp);
+if (get_config('core_competency', 'enabled')) {
+    // Manage competency frameworks page.
+    $temp = new admin_externalpage(
+        'toollpimportcsv',
+        get_string('pluginname', 'tool_lpimportcsv'),
+        new moodle_url('/admin/tool/lpimportcsv/index.php'),
+        'moodle/competency:competencymanage'
+    );
+    $ADMIN->add('competencies', $temp);
+    // Export competency framework page.
+    $temp = new admin_externalpage(
+        'toollpexportcsv',
+        get_string('exportnavlink', 'tool_lpimportcsv'),
+        new moodle_url('/admin/tool/lpimportcsv/export.php'),
+        'moodle/competency:competencymanage'
+    );
+    $ADMIN->add('competencies', $temp);
+}
 
 // No report settings.
 $settings = null;
diff --git a/admin/tool/mobile/settings.php b/admin/tool/mobile/settings.php
index 029390cec65..4f0f17a5f95 100644
--- a/admin/tool/mobile/settings.php
+++ b/admin/tool/mobile/settings.php
@@ -30,21 +30,30 @@ use core_admin\local\settings\autocomplete;
 
 if ($hassiteconfig) {
 
-    $ADMIN->add('root', new admin_category('mobileapp', new lang_string('mobileapp', 'tool_mobile')), 'development');
-
-    $temp = new admin_settingpage('mobilesettings', new lang_string('mobilesettings', 'tool_mobile'), 'moodle/site:config', false);
-
     // We should wait to the installation to finish since we depend on some configuration values that are set once
     // the admin user profile is configured.
     if (!during_initial_install()) {
         $enablemobiledocurl = new moodle_url(get_docs_url('Enable_mobile_web_services'));
         $enablemobiledoclink = html_writer::link($enablemobiledocurl, new lang_string('documentation'));
         $default = is_https() ? 1 : 0;
-        $temp->add(new admin_setting_enablemobileservice('enablemobilewebservice',
+        $optionalsubsystems = $ADMIN->locate('optionalsubsystems');
+        $optionalsubsystems->add(new admin_setting_enablemobileservice('enablemobilewebservice',
                 new lang_string('enablemobilewebservice', 'admin'),
                 new lang_string('configenablemobilewebservice', 'admin', $enablemobiledoclink), $default));
     }
 
+    $ismobilewsdisabled = empty($CFG->enablemobilewebservice);
+    $ADMIN->add('root',
+        new admin_category('mobileapp', new lang_string('mobileapp', 'tool_mobile'), $ismobilewsdisabled),
+        'development'
+    );
+
+    $temp = new admin_settingpage('mobilesettings',
+        new lang_string('mobilesettings', 'tool_mobile'),
+        'moodle/site:config',
+        $ismobilewsdisabled
+    );
+
     $temp->add(new admin_setting_configtext('tool_mobile/apppolicy', new lang_string('apppolicy', 'tool_mobile'),
         new lang_string('apppolicy_help', 'tool_mobile'), '', PARAM_URL));
 
@@ -60,8 +69,8 @@ if ($hassiteconfig) {
         $featuresnotice = $OUTPUT->render($notify);
     }
 
-    $hideappsubscription = empty($CFG->enablemobilewebservice);
-    $hideappsubscription = $hideappsubscription || (isset($CFG->disablemobileappsubscription) && !empty($CFG->disablemobileappsubscription));
+    $hideappsubscription = (isset($CFG->disablemobileappsubscription) && !empty($CFG->disablemobileappsubscription));
+    $hideappsubscription = $ismobilewsdisabled || $hideappsubscription;
 
     $ADMIN->add(
         'mobileapp',
@@ -79,7 +88,7 @@ if ($hassiteconfig) {
         'mobileauthentication',
         new lang_string('mobileauthentication', 'tool_mobile'),
         'moodle/site:config',
-        empty($CFG->enablemobilewebservice)
+        $ismobilewsdisabled
     );
 
     $temp->add(new admin_setting_heading('tool_mobile/moodleappsportalfeaturesauth', '', $featuresnotice));
@@ -123,7 +132,7 @@ if ($hassiteconfig) {
         'mobileappearance',
         new lang_string('mobileappearance', 'tool_mobile'),
         'moodle/site:config',
-        empty($CFG->enablemobilewebservice)
+        $ismobilewsdisabled
     );
 
     if (!empty($featuresnotice)) {
@@ -164,7 +173,7 @@ if ($hassiteconfig) {
         'mobilefeatures',
         new lang_string('mobilefeatures', 'tool_mobile'),
         'moodle/site:config',
-        empty($CFG->enablemobilewebservice)
+        $ismobilewsdisabled
     );
 
     if (!empty($featuresnotice)) {
diff --git a/admin/tool/moodlenet/settings.php b/admin/tool/moodlenet/settings.php
index 1767b241bcf..1eaad7869da 100644
--- a/admin/tool/moodlenet/settings.php
+++ b/admin/tool/moodlenet/settings.php
@@ -25,22 +25,29 @@
 defined('MOODLE_INTERNAL') || die();
 
 if ($hassiteconfig) {
+    // Add an enable subsystem setting to the "Advanced features" settings page.
+    $optionalsubsystems = $ADMIN->locate('optionalsubsystems');
+    $optionalsubsystems->add(new admin_setting_configcheckbox('tool_moodlenet/enablemoodlenet',
+        new lang_string('enablemoodlenet', 'tool_moodlenet'),
+        new lang_string('enablemoodlenet_desc', 'tool_moodlenet'),
+        0, 1, 0)
+    );
+
     // Create a MoodleNet category.
-    $ADMIN->add('root', new admin_category('moodlenet', get_string('pluginname', 'tool_moodlenet')));
-    // Our settings page.
-    $settings = new admin_settingpage('tool_moodlenet', get_string('moodlenetsettings', 'tool_moodlenet'));
-    $ADMIN->add('moodlenet', $settings);
+    if (get_config('tool_moodlenet', 'enablemoodlenet')) {
+        $ADMIN->add('root', new admin_category('moodlenet', get_string('pluginname', 'tool_moodlenet')));
+        // Our settings page.
+        $settings = new admin_settingpage('tool_moodlenet', get_string('moodlenetsettings', 'tool_moodlenet'));
+        $ADMIN->add('moodlenet', $settings);
 
-    $temp = new admin_setting_configcheckbox('tool_moodlenet/enablemoodlenet', get_string('enablemoodlenet', 'tool_moodlenet'),
-        new lang_string('enablemoodlenet_desc', 'tool_moodlenet'), 0, 1, 0);
-    $settings->add($temp);
+        $temp = new admin_setting_configtext('tool_moodlenet/defaultmoodlenetname',
+            get_string('defaultmoodlenetname', 'tool_moodlenet'), new lang_string('defaultmoodlenetname_desc', 'tool_moodlenet'),
+            new lang_string('defaultmoodlenetnamevalue', 'tool_moodlenet'));
+        $settings->add($temp);
 
-    $temp = new admin_setting_configtext('tool_moodlenet/defaultmoodlenetname',
-        get_string('defaultmoodlenetname', 'tool_moodlenet'), new lang_string('defaultmoodlenetname_desc', 'tool_moodlenet'),
-        new lang_string('defaultmoodlenetnamevalue', 'tool_moodlenet'));
-    $settings->add($temp);
+        $temp = new admin_setting_configtext('tool_moodlenet/defaultmoodlenet', get_string('defaultmoodlenet', 'tool_moodlenet'),
+            new lang_string('defaultmoodlenet_desc', 'tool_moodlenet'), 'https://moodle.net');
+        $settings->add($temp);
 
-    $temp = new admin_setting_configtext('tool_moodlenet/defaultmoodlenet', get_string('defaultmoodlenet', 'tool_moodlenet'),
-        new lang_string('defaultmoodlenet_desc', 'tool_moodlenet'), 'https://moodle.net');
-    $settings->add($temp);
+    }
 }