diff --git a/application/utils.inc.php b/application/utils.inc.php
index 92c34a691..376103a34 100644
--- a/application/utils.inc.php
+++ b/application/utils.inc.php
@@ -194,7 +194,7 @@ class utils
 	 */
 	public static function ShowObsoleteData()
 	{
-		$bDefault = MetaModel::GetConfig()->Get('show_obsolete_data'); // default is false
+		$bDefault = MetaModel::GetConfig()->Get('obsolescence.show_obsolete_data'); // default is false
 		$bShow = appUserPreferences::GetPref('show_obsolete_data', $bDefault);
 		if (static::IsArchiveMode())
 		{
diff --git a/core/background.inc.php b/core/background.inc.php
new file mode 100644
index 000000000..25bc762b7
--- /dev/null
+++ b/core/background.inc.php
@@ -0,0 +1,55 @@
+<?php
+// Copyright (C) 2017 Combodo SARL
+//
+//   This file is part of iTop.
+//
+//   iTop is free software; you can redistribute it and/or modify	
+//   it under the terms of the GNU Affero General Public License as published by
+//   the Free Software Foundation, either version 3 of the License, or
+//   (at your option) any later version.
+//
+//   iTop is distributed in the hope that it will be useful,
+//   but WITHOUT ANY WARRANTY; without even the implied warranty of
+//   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//   GNU Affero General Public License for more details.
+//
+//   You should have received a copy of the GNU Affero General Public License
+//   along with iTop. If not, see <http://www.gnu.org/licenses/>
+
+
+/**
+ * Tasks performed in the background
+ *
+ * @copyright   Copyright (C) 2017 Combodo SARL
+ * @license     http://opensource.org/licenses/AGPL-3.0
+ */
+
+
+class ObsolescenceDateUpdater implements iBackgroundProcess
+{
+	public function GetPeriodicity()
+	{
+		return MetaModel::GetConfig()->Get('obsolescence.date_update_interval'); // 10 mn
+	}
+
+	public function Process($iUnixTimeLimit)
+	{
+		$iCountSet = 0;
+		$iCountReset = 0;
+		$iClasses = 0;
+		foreach (MetaModel::EnumObsoletableClasses() as $sClass)
+		{
+			$oObsoletedToday = new DBObjectSearch($sClass);
+			$oObsoletedToday->AddCondition('obsolescence_flag', 1, '=');
+			$oObsoletedToday->AddCondition('obsolescence_date', null, '=');
+			$sToday = date(AttributeDate::GetSQLFormat());
+			$iCountSet += MetaModel::BulkUpdate($oObsoletedToday, array('obsolescence_date' => $sToday));
+
+			$oObsoletedToday = new DBObjectSearch($sClass);
+			$oObsoletedToday->AddCondition('obsolescence_flag', 1, '!=');
+			$oObsoletedToday->AddCondition('obsolescence_date', null, '!=');
+			$iCountReset += MetaModel::BulkUpdate($oObsoletedToday, array('obsolescence_date' => null));
+		}
+		echo "Obsolescence date updated (classes: $iClasses ; set: $iCountSet ; reset: $iCountReset)\n";
+	}
+}
diff --git a/core/config.class.inc.php b/core/config.class.inc.php
index eb0016aba..7c7dccdf3 100644
--- a/core/config.class.inc.php
+++ b/core/config.class.inc.php
@@ -929,7 +929,7 @@ class Config
 			'source_of_value' => '',
 			'show_in_conf_sample' => false,
 		),
-		'show_obsolete_data' => array(
+		'obsolescence.show_obsolete_data' => array(
 			'type' => 'bool',
 			'description' => 'Default value for the user preference "show obsolete data"',
 			'default' => false,
@@ -937,6 +937,14 @@ class Config
 			'source_of_value' => '',
 			'show_in_conf_sample' => false,
 		),
+		'obsolescence.date_update_interval' => array(
+			'type' => 'integer',
+			'description' => 'Delay in seconds between two refreshes of the obsolescence dates.',
+			'default' => 600,
+			'value' => 600,
+			'source_of_value' => '',
+			'show_in_conf_sample' => false,
+		),
 	);
 
 	public function IsProperty($sPropCode)
diff --git a/core/metamodel.class.php b/core/metamodel.class.php
index 1bf5e376d..bb0f1e39c 100644
--- a/core/metamodel.class.php
+++ b/core/metamodel.class.php
@@ -2554,13 +2554,14 @@ abstract class MetaModel
 		}
 		return $aRes;
 	}
-	public static function EnumObsoletableClasses()
+	public static function EnumObsoletableClasses($bRootClassesOnly = true)
 	{
 		$aRes = array();
 		foreach (self::GetClasses() as $sClass)
 		{
 			if (self::IsObsoletable($sClass))
 			{
+				if ($bRootClassesOnly && !static::IsRootClass($sClass)) continue;
 				$aRes[] = $sClass;
 			}
 		}
@@ -4868,6 +4869,11 @@ abstract class MetaModel
 		}
 	}
 
+	/**
+	 * @param DBObjectSearch $oFilter
+	 * @param array $aValues array of attcode => value
+	 * @return int Modified objects
+	 */
 	public static function BulkUpdate(DBObjectSearch $oFilter, array $aValues)
 	{
 		// $aValues is an array of $sAttCode => $value
@@ -4876,6 +4882,7 @@ abstract class MetaModel
 		{
 			CMDBSource::Query($sSQL);
 		}
+		return CMDBSource::AffectedRows();
 	}
 
 	/**
diff --git a/pages/preferences.php b/pages/preferences.php
index 14ed7c106..87e3cb942 100644
--- a/pages/preferences.php
+++ b/pages/preferences.php
@@ -90,7 +90,7 @@ function DisplayPreferences($oP)
 	$iDefaultPageSize = appUserPreferences::GetPref('default_page_size', MetaModel::GetConfig()->GetMinDisplayLimit());
 	$oP->add('<p>'.Dict::Format('UI:Favorites:Default_X_ItemsPerPage', '<input id="default_page_size" name="default_page_size" type="text" size="3" value="'.$iDefaultPageSize.'"/><span id="v_default_page_size"></span>').'</p>');
 
-	$bDefaultShow = appUserPreferences::GetPref('show_obsolete_data', MetaModel::GetConfig()->Get('show_obsolete_data'));
+	$bDefaultShow = appUserPreferences::GetPref('show_obsolete_data', MetaModel::GetConfig()->Get('obsolescence.show_obsolete_data'));
 	$sSelected = $bDefaultShow ? ' checked="checked"' : '';
 	$oP->add(
 		'<p>'
diff --git a/webservices/cron.php b/webservices/cron.php
index 9ea73951b..7a381b3e8 100644
--- a/webservices/cron.php
+++ b/webservices/cron.php
@@ -29,6 +29,7 @@ require_once(APPROOT.'/application/application.inc.php');
 require_once(APPROOT.'/application/nicewebpage.class.inc.php');
 require_once(APPROOT.'/application/webpage.class.inc.php');
 require_once(APPROOT.'/application/clipage.class.inc.php');
+require_once(APPROOT.'/core/background.inc.php');
 
 $sConfigFile = APPCONF.ITOP_DEFAULT_ENV.'/'.ITOP_CONFIG_FILE;
 if (!file_exists($sConfigFile))