diff --git a/admin/settings/plugins.php b/admin/settings/plugins.php
index 502d5e667ad..19bace3728f 100644
--- a/admin/settings/plugins.php
+++ b/admin/settings/plugins.php
@@ -14,6 +14,9 @@ if ($hassiteconfig) {
     $ADMIN->add('modules', new admin_category('modsettings', new lang_string('activitymodules')));
     $ADMIN->add('modsettings', new admin_page_managemods());
     foreach ($allplugins['mod'] as $module) {
+        if (!$module->is_updated()) {
+            continue;
+        }
         $module->load_settings($ADMIN, 'modsettings', $hassiteconfig);
     }
 
@@ -23,6 +26,9 @@ if ($hassiteconfig) {
     $temp->add(new admin_setting_manageformats());
     $ADMIN->add('formatsettings', $temp);
     foreach ($allplugins['format'] as $format) {
+        if (!$format->is_updated()) {
+            continue;
+        }
         $format->load_settings($ADMIN, 'formatsettings', $hassiteconfig);
     }
 
@@ -30,6 +36,9 @@ if ($hassiteconfig) {
     $ADMIN->add('modules', new admin_category('blocksettings', new lang_string('blocks')));
     $ADMIN->add('blocksettings', new admin_page_manageblocks());
     foreach ($allplugins['block'] as $block) {
+        if (!$block->is_updated()) {
+            continue;
+        }
         $block->load_settings($ADMIN, 'blocksettings', $hassiteconfig);
     }
 
@@ -38,6 +47,9 @@ if ($hassiteconfig) {
     $ADMIN->add('messageoutputs', new admin_page_managemessageoutputs());
     $ADMIN->add('messageoutputs', new admin_page_defaultmessageoutputs());
     foreach ($allplugins['message'] as $processor) {
+        if (!$processor->is_updated()) {
+            continue;
+        }
         $processor->load_settings($ADMIN, 'messageoutputs', $hassiteconfig);
     }
 
@@ -67,6 +79,9 @@ if ($hassiteconfig) {
     $ADMIN->add('authsettings', $temp);
 
     foreach ($allplugins['auth'] as $auth) {
+        if (!$auth->is_updated()) {
+            continue;
+        }
         $auth->load_settings($ADMIN, 'authsettings', $hassiteconfig);
     }
 
@@ -76,6 +91,9 @@ if ($hassiteconfig) {
     $temp->add(new admin_setting_manageenrols());
     $ADMIN->add('enrolments', $temp);
     foreach($allplugins['enrol'] as $enrol) {
+        if (!$enrol->is_updated()) {
+            continue;
+        }
         $enrol->load_settings($ADMIN, 'enrolments', $hassiteconfig);
     }
 
@@ -86,6 +104,9 @@ if ($hassiteconfig) {
     $temp->add(new admin_setting_manageeditors());
     $ADMIN->add('editorsettings', $temp);
     foreach ($allplugins['editor'] as $editor) {
+        if (!$editor->is_updated()) {
+            continue;
+        }
         $editor->load_settings($ADMIN, 'editorsettings', $hassiteconfig);
     }
 
@@ -148,6 +169,9 @@ if ($hassiteconfig) {
     $ADMIN->add('filtersettings', $temp);
 
     foreach ($allplugins['filter'] as $filter) {
+        if (!$filter->is_updated()) {
+            continue;
+        }
         $filter->load_settings($ADMIN, 'filtersettings', $hassiteconfig);
     }
 
@@ -239,6 +263,9 @@ if ($hassiteconfig) {
     $ADMIN->add('repositorysettings', new admin_externalpage('repositoryinstanceedit',
         new lang_string('editrepositoryinstance', 'repository'), $url, 'moodle/site:config', true));
     foreach ($allplugins['repository'] as $repositorytype) {
+        if (!$repositorytype->is_updated()) {
+            continue;
+        }
         $repositorytype->load_settings($ADMIN, 'repositorysettings', $hassiteconfig);
     }
 
@@ -288,6 +315,9 @@ if ($hassiteconfig) {
     $ADMIN->add('webservicesettings', $temp);
     /// links to protocol pages
     foreach ($allplugins['webservice'] as $webservice) {
+        if (!$webservice->is_updated()) {
+            continue;
+        }
         $webservice->load_settings($ADMIN, 'webservicesettings', $hassiteconfig);
     }
     /// manage token page link
@@ -363,6 +393,9 @@ if ($hassiteconfig || has_capability('moodle/question:config', $systemcontext))
 
     // Settings for particular question types.
     foreach ($allplugins['qtype'] as $qtype) {
+        if (!$qtype->is_updated()) {
+            continue;
+        }
         $qtype->load_settings($ADMIN, 'qtypesettings', $hassiteconfig);
     }
 }
@@ -374,6 +407,9 @@ if ($hassiteconfig && !empty($CFG->enableplagiarism)) {
         $CFG->wwwroot . '/' . $CFG->admin . '/plagiarism.php'));
 
     foreach ($allplugins['plagiarism'] as $plugin) {
+        if (!$plugin->is_updated()) {
+            continue;
+        }
         $plugin->load_settings($ADMIN, 'plagiarism', $hassiteconfig);
     }
 }
diff --git a/lib/adminlib.php b/lib/adminlib.php
index 7ca212768d9..37283177686 100644
--- a/lib/adminlib.php
+++ b/lib/adminlib.php
@@ -6419,8 +6419,10 @@ function admin_get_root($reload=false, $requirefulltree=true) {
  */
 function admin_apply_default_settings($node=NULL, $unconditional=true) {
     global $CFG;
+    require_once($CFG->libdir.'/pluginlib.php');
 
     if (is_null($node)) {
+        plugin_manager::reset_caches();
         $node = admin_get_root(true, true);
     }
 
@@ -6445,6 +6447,8 @@ function admin_apply_default_settings($node=NULL, $unconditional=true) {
                 $setting->write_setting_flags(null);
             }
         }
+    // Just in case somebody modifies the list of active plugins directly.
+    plugin_manager::reset_caches();
 }
 
 /**
diff --git a/lib/outputrenderers.php b/lib/outputrenderers.php
index 15de22ba808..1ca922ad352 100644
--- a/lib/outputrenderers.php
+++ b/lib/outputrenderers.php
@@ -3374,6 +3374,8 @@ class core_renderer_cli extends core_renderer {
      * @return string A template fragment for a fatal error
      */
     public function fatal_error($message, $moreinfourl, $link, $backtrace, $debuginfo = null) {
+        global $CFG;
+
         $output = "!!! $message !!!\n";
 
         if ($CFG->debugdeveloper) {
diff --git a/lib/pluginlib.php b/lib/pluginlib.php
index 9172fc1cd45..8a5ce0fc462 100644
--- a/lib/pluginlib.php
+++ b/lib/pluginlib.php
@@ -2703,6 +2703,24 @@ abstract class plugininfo_base {
         return $return;
     }
 
+    /**
+     * Is this plugin already installed and updated?
+     * @return bool true if plugin installed and upgraded.
+     */
+    public function is_updated() {
+        if (!$this->rootdir) {
+            return false;
+        }
+        if ($this->versiondb === null and $this->versiondisk === null) {
+            // There is no version.php or version info inside,
+            // for now let's pretend it is ok.
+            // TODO: return false once we require version in each plugin.
+            return true;
+        }
+
+        return ((float)$this->versiondb === (float)$this->versiondisk);
+    }
+
     /**
      * Sets {@link $displayname} property to a localized name of the plugin
      */
@@ -3968,6 +3986,9 @@ class plugininfo_format extends plugininfo_base {
         global $DB;
 
         $plugins = plugin_manager::instance()->get_installed_plugins('format');
+        if (!$plugins) {
+            return array();
+        }
         $installed = array();
         foreach ($plugins as $plugin => $version) {
             $installed[] = 'format_'.$plugin;