diff --git a/etemplate/inc/class.etemplate.inc.php b/etemplate/inc/class.etemplate.inc.php
index 03bb158e6c..b1da790f59 100644
--- a/etemplate/inc/class.etemplate.inc.php
+++ b/etemplate/inc/class.etemplate.inc.php
@@ -135,14 +135,14 @@ class etemplate_new extends etemplate_widget_template
 		{
 			if (!in_array($l_app, array($currentapp, 'custom')))
 			{
-				$langRequire[$l_app] = array('app' => $l_app, 'lang' => $lang);
+				$langRequire[$l_app] = array('app' => $l_app, 'lang' => $lang, 'etag' => translation::etag($l_app, $lang));
 			}
 		}
 		foreach(array($currentapp, 'custom') as $l_app)
 		{
 			if (isset(translation::$loaded_apps[$l_app]))
 			{
-				$langRequire[$l_app] = array('app' => $l_app, 'lang' => translation::$loaded_apps[$l_app]);
+				$langRequire[$l_app] = array('app' => $l_app, 'lang' => translation::$loaded_apps[$l_app], 'etag' => translation::etag($l_app, translation::$loaded_apps[$l_app]));
 			}
 		}
 
diff --git a/phpgwapi/inc/class.config.inc.php b/phpgwapi/inc/class.config.inc.php
index e5a5b80e56..66f85ab83c 100755
--- a/phpgwapi/inc/class.config.inc.php
+++ b/phpgwapi/inc/class.config.inc.php
@@ -378,6 +378,9 @@ class config
 				}
 			}
 		}
+		// some things need on client-side which are not direct configs
+		$client_config['phpgwapi']['lang_ctimes_md5'] = md5(json_encode(self::$configs['phpgwapi']['lang_ctimes']));
+
 		return $client_config;
 	}
 
diff --git a/phpgwapi/inc/class.translation.inc.php b/phpgwapi/inc/class.translation.inc.php
index 55d09b5338..22ee496380 100644
--- a/phpgwapi/inc/class.translation.inc.php
+++ b/phpgwapi/inc/class.translation.inc.php
@@ -428,6 +428,29 @@ class translation
 		}
 	}
 
+	/**
+	 * Get a state / etag for a given app's translations
+	 *
+	 * We currently only use a single state for all none-instance-specific apps depending on lang_ctimes.
+	 *
+	 * @param string $_app
+	 * @param string $_lang
+	 * @return string
+	 */
+	static function etag($_app, $_lang)
+	{
+		if (!in_array($_app, translation::$instance_specific_translations))
+		{
+			$etag = md5(json_encode($GLOBALS['egw_info']['server']['lang_ctimes']));
+		}
+		else
+		{
+			$etag = md5(json_encode(egw_cache::getCache(egw_cache::INSTANCE, __CLASS__, $_app.':'.$_lang)));
+		}
+		error_log(__METHOD__."('$_app', '$_lang') returning '$etag'");
+		return $etag;
+	}
+
 	/**
 	 * Loads translations for an application direct from the lang-file(s)
 	 *
diff --git a/phpgwapi/js/jsapi/egw_config.js b/phpgwapi/js/jsapi/egw_config.js
index 8034c84916..875a2576ed 100644
--- a/phpgwapi/js/jsapi/egw_config.js
+++ b/phpgwapi/js/jsapi/egw_config.js
@@ -20,7 +20,7 @@ egw.extend('config', egw.MODULE_GLOBAL, function() {
 
 	/**
 	 * Clientside config
-	 * 
+	 *
 	 * @access: private, use egw.config(_name, _app="phpgwapi")
 	 */
 	var configs = {};
@@ -28,7 +28,7 @@ egw.extend('config', egw.MODULE_GLOBAL, function() {
 	return {
 		/**
 		 * Query clientside config
-		 * 
+		 *
 		 * @param string _name name of config variable
 		 * @param string _app default "phpgwapi"
 		 * @return mixed
@@ -37,14 +37,14 @@ egw.extend('config', egw.MODULE_GLOBAL, function() {
 		{
 			if (typeof _app == 'undefined') _app = 'phpgwapi';
 
-			if (typeof configs[_app] == 'undefined') return null;
-			
-			return configs[_app][_name];
+			if (typeof this.configs[_app] == 'undefined') return null;
+
+			return this.configs[_app][_name];
 		},
-		
+
 		/**
 		 * Set clientside configuration for all apps
-		 * 
+		 *
 		 * @param array/object
 		 */
 		set_configs: function(_configs)
diff --git a/phpgwapi/js/jsapi/egw_lang.js b/phpgwapi/js/jsapi/egw_lang.js
index eb18f55b17..4b92ae3376 100644
--- a/phpgwapi/js/jsapi/egw_lang.js
+++ b/phpgwapi/js/jsapi/egw_lang.js
@@ -25,7 +25,7 @@ egw.extend('lang', egw.MODULE_GLOBAL, function() {
 
 	/**
 	 * Translations
-	 * 
+	 *
 	 * @access: private, use egw.lang() or egw.set_lang_arr()
 	 */
 	var lang_arr = {};
@@ -34,7 +34,7 @@ egw.extend('lang', egw.MODULE_GLOBAL, function() {
 	return {
 		/**
 		 * Set translation for a given application
-		 * 
+		 *
 		 * @param string _app
 		 * @param object _message message => translation pairs
 		 * @memberOf egw
@@ -46,10 +46,10 @@ egw.extend('lang', egw.MODULE_GLOBAL, function() {
 				lang_arr[_app] = _messages;
 			}
 		},
-		
+
 		/**
 		 * Translate a given phrase replacing optional placeholders
-		 * 
+		 *
 		 * @param string _msg message to translate
 		 * @param string _arg1 ... _argN
 		 */
@@ -62,7 +62,7 @@ egw.extend('lang', egw.MODULE_GLOBAL, function() {
 			}
 			var translation = _msg;
 			_msg = _msg.toLowerCase();
-			
+
 			// search apps in given order for a replacement
 			var apps = this.lang_order || ['custom', this.getAppName(), 'etemplate', 'common'];
 			for(var i = 0; i < apps.length; ++i)
@@ -75,9 +75,9 @@ egw.extend('lang', egw.MODULE_GLOBAL, function() {
 				}
 			}
 			if (arguments.length == 1) return translation;
-			
+
 			if (arguments.length == 2) return translation.replace('%1', arguments[1]);
-			
+
 			// to cope with arguments containing '%2' (eg. an urlencoded path like a referer),
 			// we first replace all placeholders '%N' with '|%N|' and then we replace all '|%N|' with arguments[N]
 			translation = translation.replace(/%([0-9]+)/g, '|%$1|');
@@ -116,9 +116,10 @@ egw.extend('lang', egw.MODULE_GLOBAL, function() {
 			{
 				if (typeof lang_arr[_apps[i].app] === "undefined")
 				{
-					jss.push(this.webserverUrl
-						+ '/phpgwapi/lang.php?app='
-						+ _apps[i].app + '&lang=' + _apps[i].lang);
+					jss.push(this.webserverUrl +
+						'/phpgwapi/lang.php?app=' + _apps[i].app +
+						'&lang=' + _apps[i].lang +
+						'&etag=' + (_apps[i].etag || this.config('lang_ctimes_md5')));
 				}
 				apps.push(_apps[i].app);
 			}
@@ -138,7 +139,7 @@ egw.extend('lang', egw.MODULE_GLOBAL, function() {
 				{
 					// Require a "ready postpone token"
 					var token = ready.readyWaitFor();
-	
+
 					// Call "readyDone" once all js files have been included.
 					files.includeJS(jss, function () {
 						ready.readyDone(token);
diff --git a/phpgwapi/js/jsapi/egw_links.js b/phpgwapi/js/jsapi/egw_links.js
index 986dc611c0..da27200b20 100644
--- a/phpgwapi/js/jsapi/egw_links.js
+++ b/phpgwapi/js/jsapi/egw_links.js
@@ -457,7 +457,7 @@ egw.extend('links', egw.MODULE_GLOBAL, function() {
 				this.value = '';
 			});
 			// need to load common translations for app-names
-			this.includeJS([this.webserverUrl+'/phpgwapi/lang.php?app=common&lang='+this.preference('lang')], function(){
+			this.langRequire(window, [{app: 'common', lang: this.preference('lang')}], function(){
 				select.append(jQuery(document.createElement('option')).attr('value', '').text(self.lang('Add')+' ...'));
 				var apps = self.link_app_list('add');
 				for(var app in apps)
diff --git a/phpgwapi/lang.php b/phpgwapi/lang.php
index 844115102a..1f9ee60137 100644
--- a/phpgwapi/lang.php
+++ b/phpgwapi/lang.php
@@ -30,23 +30,15 @@ $GLOBALS['egw_info'] = array(
 include '../header.inc.php';
 
 // use an etag with app, lang and a hash over the creation-times of all lang-files
-if (!in_array($_GET['app'], translation::$instance_specific_translations))
-{
-	$etag = '"'.$_GET['app'].'-'.$_GET['lang'].'-'.md5(serialize($GLOBALS['egw_info']['server']['lang_ctimes'])).'"';
-}
-else
-{
-	translation::add_app($_GET['app'], $_GET['lang']);
-	if (!count(translation::$lang_arr))
-	{
-		translation::add_app($_GET['app'], 'en');
-	}
-	$etag = '"'.$_GET['app'].'-'.$_GET['lang'].'-'.md5(serialize(translation::$lang_arr));
-}
+$etag = '"'.$_GET['app'].'-'.$_GET['lang'].'-'.translation::etag($_GET['app'], $_GET['lang']).'"';
+
+// tell browser/caches to cache for one day, we change url on real modifications
+$expires = 864000;	// 10days
 
 // headers to allow caching of one month
 Header('Content-Type: text/javascript; charset=utf-8');
-Header('Cache-Control: public, no-transform');
+Header('Cache-Control: public, no-transform, max-age='.$expires);
+header('Expires: ' . gmdate('D, d M Y H:i:s', time()+$expires) . ' GMT');
 Header('Pragma: cache');
 Header('ETag: '.$etag);
 
@@ -57,13 +49,10 @@ if (isset($_SERVER['HTTP_IF_NONE_MATCH']) && $_SERVER['HTTP_IF_NONE_MATCH'] == $
 	common::egw_exit();
 }
 
-if (!in_array($_GET['app'], translation::$instance_specific_translations))
+translation::add_app($_GET['app'], $_GET['lang']);
+if (!count(translation::$lang_arr))
 {
-	translation::add_app($_GET['app'], $_GET['lang']);
-	if (!count(translation::$lang_arr))
-	{
-		translation::add_app($_GET['app'], 'en');
-	}
+	translation::add_app($_GET['app'], 'en');
 }
 
 $content = 'egw.set_lang_arr("'.$_GET['app'].'", '.json_encode(translation::$lang_arr).');';