diff --git a/admin/configuration.php b/admin/configuration.php
index c6d733086..a381ef37d 100644
--- a/admin/configuration.php
+++ b/admin/configuration.php
@@ -285,6 +285,7 @@ WHERE param = \''.$row['param'].'\'
       }
     }
     $page['infos'][] = l10n('Information data registered in database');
+    pwg_activity('system', ACTIVITY_SYSTEM_CORE, 'config', array('config_section'=>$page['section']));
   }
 
   //------------------------------------------------------ $conf reinitialization
@@ -299,6 +300,7 @@ if ('sizes' == $page['section'] and isset($_GET['action']) and 'restore_settings
   clear_derivative_cache();
 
   $page['infos'][] = l10n('Your configuration settings are saved');
+  pwg_activity('system', ACTIVITY_SYSTEM_CORE, 'config', array('config_section'=>$page['section'],'config_action'=>$_GET['action']));
 }
 
 //----------------------------------------------------- template initialization
diff --git a/admin/include/configuration_sizes_process.inc.php b/admin/include/configuration_sizes_process.inc.php
index 40a2b7125..7820308b4 100644
--- a/admin/include/configuration_sizes_process.inc.php
+++ b/admin/include/configuration_sizes_process.inc.php
@@ -245,6 +245,7 @@ if (count($errors) == 0)
   }
 
   $page['infos'][] = l10n('Your configuration settings are saved');
+  pwg_activity('system', ACTIVITY_SYSTEM_CORE, 'config', array('config_section'=>'sizes'));
 }
 else
 {
diff --git a/admin/include/configuration_watermark_process.inc.php b/admin/include/configuration_watermark_process.inc.php
index e0a0bb9ff..083ab64e8 100644
--- a/admin/include/configuration_watermark_process.inc.php
+++ b/admin/include/configuration_watermark_process.inc.php
@@ -196,6 +196,7 @@ if (count($errors) == 0)
   }
 
   $page['infos'][] = l10n('Your configuration settings are saved');
+  pwg_activity('system', ACTIVITY_SYSTEM_CORE, 'config', array('config_section'=>'watermark'));
 }
 else
 {
diff --git a/admin/include/plugins.class.php b/admin/include/plugins.class.php
index 9f2227b75..92a469495 100644
--- a/admin/include/plugins.class.php
+++ b/admin/include/plugins.class.php
@@ -117,6 +117,8 @@ class plugins
       $plugin_maintain = self::build_maintain_class($plugin_id);
     }
 
+    $activity_details = array('plugin_id'=>$plugin_id);
+
     $errors = array();
 
     switch ($action)
@@ -128,6 +130,7 @@ class plugins
         }
 
         $plugin_maintain->install($this->fs_plugins[$plugin_id]['version'], $errors);
+        $activity_details['version'] = $this->fs_plugins[$plugin_id]['version'];
 
         if (empty($errors))
         {
@@ -137,16 +140,22 @@ INSERT INTO '. PLUGINS_TABLE .' (id,version)
 ;';
           pwg_query($query);
         }
+        else
+        {
+          $activity_details['result'] = 'error';
+        }
         break;
 
       case 'update':
         $previous_version = $this->fs_plugins[$plugin_id]['version'];
+        $activity_details['from_version'] = $previous_version;
         $errors[0] = $this->extract_plugin_files('upgrade', $options['revision'], $plugin_id);
 
         if ($errors[0] === 'ok')
         {
           $this->get_fs_plugin($plugin_id); // refresh plugins list
           $new_version = $this->fs_plugins[$plugin_id]['version'];
+          $activity_details['to_version'] = $new_version;
 
           $plugin_maintain = self::build_maintain_class($plugin_id);
           $plugin_maintain->update($previous_version, $new_version, $errors);
@@ -161,6 +170,11 @@ UPDATE '. PLUGINS_TABLE .'
             pwg_query($query);
           }
         }
+        else
+        {
+          $activity_details['result'] = 'error';
+        }
+
 
         break;
 
@@ -179,6 +193,7 @@ UPDATE '. PLUGINS_TABLE .'
         if (empty($errors))
         {
           $plugin_maintain->activate($crt_db_plugin['version'], $errors);
+          $activity_details['version'] = $crt_db_plugin['version'];
         }
 
         if (empty($errors))
@@ -190,11 +205,16 @@ UPDATE '. PLUGINS_TABLE .'
 ;';
           pwg_query($query);
         }
+        else
+        {
+          $activity_details['result'] = 'error';
+        }
         break;
 
       case 'deactivate':
         if (!isset($crt_db_plugin) or $crt_db_plugin['state'] != 'active')
         {
+          $activity_details['result'] = 'error';
           break;
         }
 
@@ -206,13 +226,27 @@ UPDATE '. PLUGINS_TABLE .'
         pwg_query($query);
 
         $plugin_maintain->deactivate();
+
+        if (isset($crt_db_plugin['version']))
+        {
+          $activity_details['version'] = $crt_db_plugin['version'];
+        }
+
         break;
 
       case 'uninstall':
         if (!isset($crt_db_plugin))
         {
+          $activity_details['result'] = 'error';
+          $activity_details['error'] = 'plugin not installed';
           break;
         }
+
+        if (isset($crt_db_plugin['version']))
+        {
+          $activity_details['version'] = $crt_db_plugin['version'];
+        }
+
         if ($crt_db_plugin['state'] == 'active')
         {
           $this->perform_action('deactivate', $plugin_id);
@@ -236,17 +270,29 @@ DELETE FROM '. PLUGINS_TABLE .'
       case 'delete':
         if (!empty($crt_db_plugin))
         {
+          if (isset($crt_db_plugin['version']))
+          {
+            $activity_details['db_version'] = $crt_db_plugin['version'];
+          }
+
           $this->perform_action('uninstall', $plugin_id);
         }
         if (!isset($this->fs_plugins[$plugin_id]))
         {
           break;
         }
+        else
+        {
+          $activity_details['fs_version'] = $this->fs_plugins[$plugin_id]['version'];
+        }
+
         include_once(PHPWG_ROOT_PATH.'admin/include/functions.php');
         deltree(PHPWG_PLUGINS_PATH . $plugin_id, PHPWG_PLUGINS_PATH . 'trash');
         break;
     }
 
+    pwg_activity('system', ACTIVITY_SYSTEM_PLUGIN, $action, $activity_details);
+
     return $errors;
   }
 
diff --git a/admin/include/themes.class.php b/admin/include/themes.class.php
index e3d421824..47191a9e4 100644
--- a/admin/include/themes.class.php
+++ b/admin/include/themes.class.php
@@ -96,6 +96,7 @@ class themes
     $theme_maintain = self::build_maintain_class($theme_id);
 
     $errors = array();
+    $activity_details = array('theme_id'=>$theme_id);
 
     switch ($action)
     {
@@ -144,6 +145,8 @@ INSERT INTO '.THEMES_TABLE.'
 ;';
           pwg_query($query);
 
+          $activity_details['version'] = $this->fs_themes[$theme_id]['version'];
+
           if ($this->fs_themes[$theme_id]['mobile'])
           {
             conf_update_param('mobile_theme', $theme_id);
@@ -236,6 +239,9 @@ DELETE
         $this->set_default_theme($theme_id);
         break;
     }
+
+    pwg_activity('system', ACTIVITY_SYSTEM_THEME, $action, $activity_details);
+
     return $errors;
   }
 
@@ -577,7 +583,7 @@ SELECT
    * @param string - remote revision identifier (numeric)
    * @param string - theme id or extension id
    */
-  function extract_theme_files($action, $revision, $dest)
+  function extract_theme_files($action, $revision, $dest, &$theme_id=null)
   {
     global $logger;
 
@@ -614,13 +620,13 @@ SELECT
             $root = dirname($main_filepath); // main.inc.php path in archive
             if ($action == 'upgrade')
             {
-              $extract_path = PHPWG_THEMES_PATH . $dest;
+              $theme_id = $dest;
             }
             else
             {
-              $extract_path = PHPWG_THEMES_PATH . ($root == '.' ? 'extension_' . $dest : basename($root));
+              $theme_id = ($root == '.' ? 'extension_' . $dest : basename($root));
             }
-
+            $extract_path = PHPWG_THEMES_PATH . $theme_id;
             $logger->debug(__FUNCTION__.', $extract_path = '.$extract_path);
 
             if (
diff --git a/admin/include/updates.class.php b/admin/include/updates.class.php
index 8d24f6987..56ca8d0bf 100644
--- a/admin/include/updates.class.php
+++ b/admin/include/updates.class.php
@@ -460,6 +460,8 @@ class updates
 
     if ($check_current_version and !version_compare($upgrade_to, PHPWG_VERSION, '>'))
     {
+      // TODO why redirect to a plugin page? maybe a remaining code from when
+      // the update system was provided as a plugin?
       redirect(get_root_url().'admin.php?page=plugin-'.basename(dirname(__FILE__)));
     }
 
@@ -552,6 +554,8 @@ class updates
 
             deltree(PHPWG_ROOT_PATH.$conf['data_location'].'update');
             invalidate_user_cache(true);
+            pwg_activity('system', ACTIVITY_SYSTEM_CORE, 'update', array('from_version'=>PHPWG_VERSION, 'to_version'=>$upgrade_to));
+
             if ($step == 2)
             {
               // only delete compiled templates on minor update. Doing this on
diff --git a/admin/maintenance_actions.php b/admin/maintenance_actions.php
index fa53c9ac8..8d6db5674 100644
--- a/admin/maintenance_actions.php
+++ b/admin/maintenance_actions.php
@@ -13,6 +13,7 @@ fs_quick_check();
 // +-----------------------------------------------------------------------+
 
 $action = isset($_GET['action']) ? $_GET['action'] : '';
+$register_activity = true;
 
 switch ($action)
 {
@@ -24,6 +25,7 @@ switch ($action)
   case 'lock_gallery' :
   {
     conf_update_param('gallery_locked', 'true');
+    pwg_activity('system', ACTIVITY_SYSTEM_CORE, 'maintenance', array('maintenance_action'=>$action));
     redirect(get_root_url().'admin.php?page=maintenance');
     break;
   }
@@ -31,6 +33,7 @@ switch ($action)
   {
     conf_update_param('gallery_locked', 'false');
     $_SESSION['page_infos'] = array(l10n('Gallery unlocked'));
+    pwg_activity('system', ACTIVITY_SYSTEM_CORE, 'maintenance', array('maintenance_action'=>$action));
     redirect(get_root_url().'admin.php?page=maintenance');
     break;
   }
@@ -243,10 +246,15 @@ DELETE
 
   default :
   {
+    $register_activity = false;
     break;
   }
 }
 
+if ($register_activity)
+{
+  pwg_activity('system', ACTIVITY_SYSTEM_CORE, 'maintenance', array('maintenance_action'=>$action));
+}
 
 // +-----------------------------------------------------------------------+
 // |                             template init                             |
diff --git a/admin/plugins_new.php b/admin/plugins_new.php
index 40f788e7c..2c28eb98f 100644
--- a/admin/plugins_new.php
+++ b/admin/plugins_new.php
@@ -50,6 +50,19 @@ if (isset($_GET['installstatus']))
 
       $page['infos'][] = l10n('Plugin has been successfully copied');
       $page['infos'][] = '<a href="'. $activate_url . '">' . l10n('Activate it now') . '</a>';
+
+      if (isset($plugins->fs_plugins[$_GET['plugin_id']]))
+      {
+        pwg_activity(
+          'system',
+          ACTIVITY_SYSTEM_PLUGIN,
+          'install',
+          array(
+            'plugin_id' => $_GET['plugin_id'],
+            'version' => $plugins->fs_plugins[$_GET['plugin_id']]['version'],
+          )
+        );
+      }
       break;
 
     case 'temp_path_error':
diff --git a/admin/themes_new.php b/admin/themes_new.php
index b3b011371..12dfc148c 100644
--- a/admin/themes_new.php
+++ b/admin/themes_new.php
@@ -44,10 +44,11 @@ if (isset($_GET['revision']) and isset($_GET['extension']))
     $install_status = $themes->extract_theme_files(
       'install',
       $_GET['revision'],
-      $_GET['extension']
+      $_GET['extension'],
+      $theme_id
       );
     
-    redirect($base_url.'&installstatus='.$install_status);
+    redirect($base_url.'&installstatus='.$install_status.'&theme_id='.$theme_id);
   }
 }
 
@@ -61,6 +62,19 @@ if (isset($_GET['installstatus']))
   {
     case 'ok':
       $page['infos'][] = l10n('Theme has been successfully installed');
+
+      if (isset($themes->fs_themes[$_GET['theme_id']]))
+      {
+        pwg_activity(
+          'system',
+          ACTIVITY_SYSTEM_THEME,
+          'install',
+          array(
+            'theme_id' => $_GET['theme_id'],
+            'version' => $themes->fs_themes[$_GET['theme_id']]['version'],
+          )
+        );
+      }
       break;
 
     case 'temp_path_error':
diff --git a/admin/user_activity.php b/admin/user_activity.php
index ef55a8aa7..d85a17592 100644
--- a/admin/user_activity.php
+++ b/admin/user_activity.php
@@ -101,7 +101,9 @@ SELECT
     performed_by, 
     COUNT(*) as counter 
   FROM '.ACTIVITY_TABLE.'
-  group by performed_by;';
+  WHERE object != \'system\'
+  GROUP BY performed_by
+;';
 
 $nb_lines_for_user = query2array($query, 'performed_by', 'counter');
 
diff --git a/include/constants.php b/include/constants.php
index 630c119b7..90329ef6d 100644
--- a/include/constants.php
+++ b/include/constants.php
@@ -30,6 +30,11 @@ define('ACCESS_ADMINISTRATOR', 3);
 define('ACCESS_WEBMASTER', 4);
 define('ACCESS_CLOSED', 5);
 
+// System activities
+define('ACTIVITY_SYSTEM_CORE', 1);
+define('ACTIVITY_SYSTEM_PLUGIN', 2);
+define('ACTIVITY_SYSTEM_THEME', 3);
+
 // Sanity checks
 define('PATTERN_ID', '/^\d+$/');
 
diff --git a/include/functions.inc.php b/include/functions.inc.php
index 1cb39b901..289fb003a 100644
--- a/include/functions.inc.php
+++ b/include/functions.inc.php
@@ -536,6 +536,13 @@ function pwg_activity($object, $object_id, $action, $details=array())
     return;
   }
 
+  if (isset($_REQUEST['method']) and 'pwg.plugins.performAction' == $_REQUEST['method'] and $_REQUEST['action'] != $action)
+  {
+    // for example, if you "restore" a plugin, the internal sequence will perform deactivate/uninstall/install/activate.
+    // We only want to keep the last call to pwg_activity with the "restore" action.
+    return;
+  }
+
   $object_ids = $object_id;
   if (!is_array($object_id))
   {
@@ -556,6 +563,13 @@ function pwg_activity($object, $object_id, $action, $details=array())
     }
   }
 
+  if ('autoupdate' == $action)
+  {
+    // autoupdate on a plugin can happen anywhere, the "script/method" is not meaningfull
+    unset($details['method']);
+    unset($details['script']);
+  }
+
   $user_agent = null;
   if ('user' == $object and 'login' == $action and isset($_SERVER['HTTP_USER_AGENT']))
   {
@@ -588,7 +602,7 @@ function pwg_activity($object, $object_id, $action, $details=array())
 
   foreach ($object_ids as $loop_object_id)
   {
-    $performed_by = $user['id'];
+    $performed_by = $user['id'] ?? 0; // on a plugin autoupdate, $user is not yet loaded
 
     if ('logout' == $action)
     {
diff --git a/include/functions_plugins.inc.php b/include/functions_plugins.inc.php
index 468659605..b5862496b 100644
--- a/include/functions_plugins.inc.php
+++ b/include/functions_plugins.inc.php
@@ -385,6 +385,9 @@ function autoupdate_plugin(&$plugin)
         safe_version_compare($plugin['version'], $fs_version, '<')
       )
   ) {
+    $old_version = $plugin['version'];
+    $new_version = $fs_version;
+
     $plugin['version'] = $fs_version;
 
     $maintain_file = PHPWG_PLUGINS_PATH.$plugin['id'].'/maintain.class.php';
@@ -407,8 +410,9 @@ function autoupdate_plugin(&$plugin)
       $plugin_maintain->update($plugin['version'], $fs_version, $page['errors']);
     }
 
-    // update database (only on production)
-    if ($plugin['version'] != 'auto')
+    // update database (only on production). We want to avoid registering an "auto" to "auto" update,
+    // which happens for each "version=auto" plugin on each page load.
+    if ($new_version != $old_version)
     {
       $query = '
 UPDATE '. PLUGINS_TABLE .'
@@ -416,6 +420,8 @@ UPDATE '. PLUGINS_TABLE .'
   WHERE id = "'. $plugin['id'] .'"
 ;';
       pwg_query($query);
+
+      pwg_activity('system', ACTIVITY_SYSTEM_PLUGIN, 'autoupdate', array('plugin_id'=>$plugin['id'], 'from_version'=>$old_version, 'to_version'=>$new_version));
     }
   }
 }
diff --git a/include/ws_functions/pwg.extensions.php b/include/ws_functions/pwg.extensions.php
index cb34295f7..c983d8bd6 100644
--- a/include/ws_functions/pwg.extensions.php
+++ b/include/ws_functions/pwg.extensions.php
@@ -190,6 +190,20 @@ function ws_extensions_update($params, $service)
   {
     $upgrade_status = $extension->extract_theme_files('upgrade', $revision, $extension_id);
     $extension_name = $extension->fs_themes[$extension_id]['name'];
+
+    $activity_details = array('theme_id'=>$extension_id, 'from_version'=>$extension->fs_themes[$extension_id]['version']);
+
+    if ('ok' == $upgrade_status)
+    {
+      $extension->get_fs_themes(); // refresh list
+      $activity_details['to_version'] = $extension->fs_themes[$extension_id]['version'];
+    }
+    else
+    {
+      $activity_details['result'] = 'error';
+    }
+
+    pwg_activity('system', ACTIVITY_SYSTEM_THEME, 'update', $activity_details);
   }
   else if ($type == 'languages')
   {
diff --git a/include/ws_functions/pwg.php b/include/ws_functions/pwg.php
index 1153cd724..86457c84b 100644
--- a/include/ws_functions/pwg.php
+++ b/include/ws_functions/pwg.php
@@ -446,23 +446,24 @@ SELECT
     occured_on,
     details,
     user_agent
-  FROM '.ACTIVITY_TABLE;
+  FROM '.ACTIVITY_TABLE.'
+  WHERE object != \'system\'';
 
   if (isset($param['uid']))
   {
     $query.= '
-  WHERE performed_by = '.$param['uid'];
+    AND performed_by = '.$param['uid'];
   }
   elseif ('none' == $conf['activity_display_connections'])
   {
     $query.= '
-  WHERE action NOT IN (\'login\', \'logout\')';
+    AND action NOT IN (\'login\', \'logout\')';
   }
   elseif ('admins_only' == $conf['activity_display_connections'])
   {
     include_once(PHPWG_ROOT_PATH.'admin/include/functions.php');
     $query.= '
-  WHERE NOT (action IN (\'login\', \'logout\') AND object_id NOT IN ('.implode(',', get_admins()).'))';
+    AND NOT (action IN (\'login\', \'logout\') AND object_id NOT IN ('.implode(',', get_admins()).'))';
   }
 
   $query.= '