diff --git a/conlite/classes/class.inuse.php b/conlite/classes/class.inuse.php
index 13cdf76..c610667 100644
--- a/conlite/classes/class.inuse.php
+++ b/conlite/classes/class.inuse.php
@@ -65,6 +65,10 @@ class InUseCollection extends ItemCollection
         $objectid = Contenido_Security::escapeDB($objectid, null);
         $session  = Contenido_Security::escapeDB($session, null);
         $user     = Contenido_Security::escapeDB($user, null);
+        
+        if(empty($type)) {
+            $type = "unknown";
+        }
 
         $this->select("type = '".$type."' AND objectid = '".$objectid."'");
 
diff --git a/conlite/main.php b/conlite/main.php
index 5dcd6a6..5e665c0 100644
--- a/conlite/main.php
+++ b/conlite/main.php
@@ -1,4 +1,5 @@
 <?php
+
 /**
  * Project: 
  * Contenido Content Management System
@@ -31,7 +32,6 @@
  * }}
  * 
  */
-
 if (!defined("CON_FRAMEWORK")) {
     define("CON_FRAMEWORK", true);
 }
@@ -41,14 +41,14 @@ include_once ('./includes/startup.php');
 
 $cfg["debug"]["backend_exectime"]["fullstart"] = getmicrotime();
 
-cInclude ("includes", 'functions.api.php');
-cInclude ("includes", 'functions.forms.php');
+cInclude("includes", 'functions.api.php');
+cInclude("includes", 'functions.forms.php');
 
 page_open(array('sess' => 'Contenido_Session',
-                'auth' => 'Contenido_Challenge_Crypt_Auth',
-                'perm' => 'Contenido_Perm'));
+    'auth' => 'Contenido_Challenge_Crypt_Auth',
+    'perm' => 'Contenido_Perm'));
 
-i18nInit($cfg["path"]["contenido"].$cfg["path"]["locale"], $belang);
+i18nInit($cfg["path"]["contenido"] . $cfg["path"]["locale"], $belang);
 
 /**
  * Bugfix
@@ -59,20 +59,19 @@ i18nInit($cfg["path"]["contenido"].$cfg["path"]["locale"], $belang);
 //includePluginConf();
 require_once $cfg['path']['contenido'] . $cfg['path']['includes'] . 'functions.includePluginConf.php';
 
-cInclude ("includes", 'cfg_language_de.inc.php');
+cInclude("includes", 'cfg_language_de.inc.php');
 
-if ($cfg["use_pseudocron"] == true)
-{
+if ($cfg["use_pseudocron"] == true) {
     /* Include cronjob-Emulator, but only for frame 1 */
-    if($frame == 4) {        
+    if ($frame == 4) {
         $sess->freeze();
         $oldpwd = getcwd();
 
-        chdir($cfg["path"]["contenido"].$cfg["path"]["cronjobs"]);
+        chdir($cfg["path"]["contenido"] . $cfg["path"]["cronjobs"]);
         cInclude("includes", "pseudo-cron.inc.php");
         chdir($oldpwd);
 
-        if($bJobRunned == true) {
+        if ($bJobRunned == true) {
             // Some cronjobs might overwrite important system variables.
             // We are thaw'ing the session again to re-register these variables.
             $sess->thaw();
@@ -82,18 +81,16 @@ if ($cfg["use_pseudocron"] == true)
 
 
 /* Remove all own marks, only for frame 1 and 4  if $_REQUEST['appendparameters'] == 'filebrowser'
-   filebrowser is used in tiny in this case also do not remove session marks*/
-if (($frame == 1 || $frame == 4) && isset($_REQUEST['appendparameters']) && $_REQUEST['appendparameters'] != 'filebrowser')
-{
-	$col = new InUseCollection;
-	$col->removeSessionMarks($sess->id);
+  filebrowser is used in tiny in this case also do not remove session marks */
+if (($frame == 1 || $frame == 4) && isset($_REQUEST['appendparameters']) && $_REQUEST['appendparameters'] != 'filebrowser') {
+    $col = new InUseCollection;
+    $col->removeSessionMarks($sess->id);
 }
 
 /* If the override flag is set, override a specific InUseItem */
-if (isset($overrideid) && isset($overridetype))
-{
-	$col = new InUseCollection;
-	$col->removeItemMarks($overridetype, $overrideid);
+if (isset($overrideid) && isset($overridetype)) {
+    $col = new InUseCollection;
+    $col->removeItemMarks($overridetype, $overrideid);
 }
 
 # Create Contenido classes
@@ -111,53 +108,47 @@ $currentuser->loadUserByUserID($auth->auth["uid"]);
 
 
 # change Client
-if (isset($changeclient) && is_numeric($changeclient) ) {
+if (isset($changeclient) && is_numeric($changeclient)) {
     $client = $changeclient;
     unset($lang);
 }
 
 # Sprache wechseln
-if (isset($changelang) && is_numeric($changelang) ) {
-	unset($area_rights);
-	unset($item_rights);
+if (isset($changelang) && is_numeric($changelang)) {
+    unset($area_rights);
+    unset($item_rights);
 
     $lang = $changelang;
 }
 
-if (!is_numeric($client) ||
-	(!$perm->have_perm_client("client[".$client."]") &&
-	 !$perm->have_perm_client("admin[".$client."]")))
-{
-	 // use first client which is accessible
+if (!is_numeric($client) || (!$perm->have_perm_client("client[" . $client . "]") && !$perm->have_perm_client("admin[" . $client . "]"))) {
+    // use first client which is accessible
     $sess->register("client");
-    $sql = "SELECT idclient FROM ".$cfg["tab"]["clients"]." ORDER BY idclient ASC";
+    $sql = "SELECT idclient FROM " . $cfg["tab"]["clients"] . " ORDER BY idclient ASC";
     $db->query($sql);
 
-    while ($db->next_record())
-    {
-    	$mclient = $db->f("idclient");
+    while ($db->next_record()) {
+        $mclient = $db->f("idclient");
 
-    	if ($perm->have_perm_client("client[".$mclient."]") ||
-    		$perm->have_perm_client("admin[".$mclient."]") )
-    	{
-    		unset($lang);
-    		$client = $mclient;
-    		break;
-    	}
+        if ($perm->have_perm_client("client[" . $mclient . "]") || $perm->have_perm_client("admin[" . $mclient . "]")) {
+            unset($lang);
+            $client = $mclient;
+            break;
+        }
     }
 } else {
-	$sess->register("client");
+    $sess->register("client");
 }
 
 if (!is_numeric($lang) || $lang == "") {
     $sess->register("lang");
     # search for the first language of this client
-    $sql = "SELECT * FROM ".$cfg["tab"]["lang"]." AS A, ".$cfg["tab"]["clients_lang"]." AS B WHERE A.idlang=B.idlang AND idclient='".Contenido_Security::toInteger($client)."' ORDER BY A.idlang ASC";
+    $sql = "SELECT * FROM " . $cfg["tab"]["lang"] . " AS A, " . $cfg["tab"]["clients_lang"] . " AS B WHERE A.idlang=B.idlang AND idclient='" . Contenido_Security::toInteger($client) . "' ORDER BY A.idlang ASC";
     $db->query($sql);
     $db->next_record();
     $lang = $db->f("idlang");
 } else {
-	$sess->register("lang");
+    $sess->register("lang");
 }
 
 // send right encoding http header
@@ -166,11 +157,10 @@ sendEncodingHeader($db, $cfg, $lang);
 $perm->load_permissions();
 
 # Create Contenido classes
-$xml        = new XML_doc;
-$tpl        = new Template;
-$backend    = new Contenido_Backend;
+$xml = new XML_doc;
+$tpl = new Template;
+$backend = new Contenido_Backend;
 //$backend->debug=true;
-
 # Register session variables
 $sess->register("sess_area");
 
@@ -184,7 +174,7 @@ $sess->register("cfgClient");
 $sess->register("errsite_idcat");
 $sess->register("errsite_idart");
 
-if(!isset($cfgClient) || !isset($cfgClient["set"]) || $cfgClient["set"] != "set") {
+if (!isset($cfgClient) || !isset($cfgClient["set"]) || $cfgClient["set"] != "set") {
     rereadClients();
 }
 
@@ -192,9 +182,8 @@ if(!isset($cfgClient) || !isset($cfgClient["set"]) || $cfgClient["set"] != "set"
 # Load all actions from the DB
 # and check if permission is
 # granted.
-if ($cfg["debug"]["rendering"] == true)
-{
-	$oldmemusage = memory_get_usage();
+if ($cfg["debug"]["rendering"] == true) {
+    $oldmemusage = memory_get_usage();
 }
 # Select frameset
 $backend->setFrame($frame);
@@ -209,20 +198,17 @@ $cfg["debug"]["backend_exectime"]["start"] = getmicrotime();
 # one file is required.
 if (is_array($backend->getFile('inc'))) {
     foreach ($backend->getFile('inc') as $filename) {
-            include_once($cfg['path']['contenido'].$filename);
-
+        include_once($cfg['path']['contenido'] . $filename);
     }
 }
 
 # If $action is set -> User klicked some button/link
 # get the appopriate code for this action and evaluate it.
 
-if (isset($action) && $action != "")
-{
-	if (!isset($idart))
-	{
-		$idart = 0;
-	}
+if (isset($action) && $action != "") {
+    if (!isset($idart)) {
+        $idart = 0;
+    }
 
     $backend->log($idcat, $idart, $client, $lang, $action);
 }
@@ -231,15 +217,14 @@ if (isset($action) && $action != "")
 if (isset($action)) {
     if ($backend->getCode($action) != '') {
         if ($backend->debug == 1) {
-            echo '<pre style="font-family: verdana; font-size: 10px"><b>Executing:</b>'."\n";
-            echo $backend->getCode($action)."\n";
+            echo '<pre style="font-family: verdana; font-size: 10px"><b>Executing:</b>' . "\n";
+            echo $backend->getCode($action) . "\n";
             echo '</pre>';
         }
         eval($backend->getCode($action));
-
     } else {
         if ($backend->debug == 1) {
-            echo '<pre style="font-family: verdana; font-size: 10px"><b>Executing:</b>'."\n";
+            echo '<pre style="font-family: verdana; font-size: 10px"><b>Executing:</b>' . "\n";
             echo "no code available in action\n";
             echo '</pre>';
         }
@@ -248,46 +233,36 @@ if (isset($action)) {
 
 # Include the 'main' file for the selected area.
 # Usually there is only one main file
-if (is_array($backend->getFile('main')))
-{
-	foreach ($backend->getFile('main') as $id => $filename)
-	{
-  	include_once($cfg['path']['contenido'].$filename);
-  }
-
-}
-elseif( $frame == 3 )
-{
-    include_once($cfg['path']['contenido'].$cfg['path']['includes'] ."include.default_subnav.php" );
-}
-else
-{
-	include_once($cfg['path']['contenido'].$cfg['path']['includes'] ."include.blank.php");
+if (is_array($backend->getFile('main'))) {
+    foreach ($backend->getFile('main') as $id => $filename) {
+        include_once($cfg['path']['contenido'] . $filename);
+    }
+} elseif ($frame == 3) {
+    include_once($cfg['path']['contenido'] . $cfg['path']['includes'] . "include.default_subnav.php" );
+} else {
+    include_once($cfg['path']['contenido'] . $cfg['path']['includes'] . "include.blank.php");
 }
 
 $cfg["debug"]["backend_exectime"]["end"] = getmicrotime();
 
-if ($cfg["debug"]["rendering"] == true)
-{
-	echo "Building this page (excluding contenido includes) took: " . ($cfg["debug"]["backend_exectime"]["end"] - $cfg["debug"]["backend_exectime"]["start"])." seconds<br>";
-	echo "Building the complete page took: " . ($cfg["debug"]["backend_exectime"]["end"] - $cfg["debug"]["backend_exectime"]["fullstart"])." seconds<br>";
+if ($cfg["debug"]["rendering"] == true) {
+    echo "Building this page (excluding contenido includes) took: " . ($cfg["debug"]["backend_exectime"]["end"] - $cfg["debug"]["backend_exectime"]["start"]) . " seconds<br>";
+    echo "Building the complete page took: " . ($cfg["debug"]["backend_exectime"]["end"] - $cfg["debug"]["backend_exectime"]["fullstart"]) . " seconds<br>";
 
-	echo "Include memory usage: ".human_readable_size(memory_get_usage()-$oldmemusage)."<br>";
-	echo "Complete memory usage: ".human_readable_size(memory_get_usage())."<br>";
+    echo "Include memory usage: " . human_readable_size(memory_get_usage() - $oldmemusage) . "<br>";
+    echo "Complete memory usage: " . human_readable_size(memory_get_usage()) . "<br>";
 }
 
 /**
  * Start User Tracking (who is online)
  *
- **/
+ * */
 $oActiveUser = new ActiveUsers($db, $cfg, $auth);
 $oActiveUser->startUsersTracking();
 /**
  *
  * End of the User Tracking
  */
-
 $db->disconnect();
 page_close();
-
 ?>
\ No newline at end of file
diff --git a/setup/data/tables.txt b/setup/data/tables.txt
index cb2f1e1..fe40fe9 100644
--- a/setup/data/tables.txt
+++ b/setup/data/tables.txt
@@ -226,10 +226,10 @@
 "groups";"perms";"mediumtext";"YES";"";"";"";""
 "groups";"description";"varchar(255)";"YES";"";"";"";""
 "inuse";"idinuse";"int(10)";"NO";"PRI";"0";"";"1"
-"inuse";"type";"varchar(32)";"NO";"";"";"";""
-"inuse";"objectid";"varchar(32)";"NO";"";"";"";""
-"inuse";"session";"varchar(32)";"NO";"";"";"";""
-"inuse";"userid";"varchar(32)";"NO";"";"";"";""
+"inuse";"type";"varchar(32)";"YES";"";"";"";""
+"inuse";"objectid";"varchar(32)";"YES";"";"";"";""
+"inuse";"session";"varchar(32)";"YES";"";"";"";""
+"inuse";"userid";"varchar(32)";"YES";"";"";"";""
 "keywords";"idkeyword";"int(10)";"NO";"PRI";"0";"";"1"
 "keywords";"keyword";"varchar(50)";"NO";"MUL";"";"";""
 "keywords";"exp";"text";"NO";"";"";"";""
diff --git a/setup/dbupdate.php b/setup/dbupdate.php
index 7d93e85..ab89369 100644
--- a/setup/dbupdate.php
+++ b/setup/dbupdate.php
@@ -52,11 +52,7 @@ if (checkMySQLDatabaseCreation($db, $_SESSION['dbname'])) {
     $db = getSetupMySQLDBConnection();
 }
 
-$currentstep = $_GET['step'];
-
-if ($currentstep == 0) {
-    $currentstep = 1;
-}
+$currentstep = (empty($_GET['step']))?1:filter_input(INPUT_GET, "step", FILTER_SANITIZE_NUMBER_INT);
 
 // Count DB Chunks
 $file = fopen('data/tables.txt', 'r');
diff --git a/setup/lib/defines.php b/setup/lib/defines.php
index 79020a0..bf230ce 100644
--- a/setup/lib/defines.php
+++ b/setup/lib/defines.php
@@ -56,6 +56,6 @@ define('C_SETUP_STEPFILE', 'images/steps/s%d.png');
 define('C_SETUP_STEPFILE_ACTIVE', 'images/steps/s%da.png');
 define('C_SETUP_STEPWIDTH', 28);
 define('C_SETUP_STEPHEIGHT', 28);
-define('C_SETUP_MIN_PHP_VERSION', '5.3');
-define('C_SETUP_VERSION', '2.0.1');
+define('C_SETUP_MIN_PHP_VERSION', '5.6');
+define('C_SETUP_VERSION', '2.1.0');
 ?>
\ No newline at end of file
diff --git a/setup/lib/functions.mysql.php b/setup/lib/functions.mysql.php
index 746d178..83ccdba 100644
--- a/setup/lib/functions.mysql.php
+++ b/setup/lib/functions.mysql.php
@@ -62,7 +62,7 @@ function doMySQLConnect($host, $username, $password) {
     //$sFile = '../data/logs/setup_queries.txt';
     //file_put_contents($sFile, $db->getServerInfo(), FILE_APPEND);
     //chmod($sFile, 0666);
-    if ($db->connect() == 0) {
+    if (empty($db->connect())) {
         return array($db, false);
     } else {
         return array($db, true);
diff --git a/setup/lib/startup.php b/setup/lib/startup.php
index 3aed609..fe7cec9 100644
--- a/setup/lib/startup.php
+++ b/setup/lib/startup.php
@@ -28,7 +28,7 @@ if (!defined('CON_FRAMEWORK')) {
 define('CON_BE_PATH', '../conlite/');
 
 // uncomment this lines during development if needed
-error_reporting(E_ALL ^E_NOTICE);
+error_reporting(E_ALL ^ E_NOTICE);
 ini_set("display_errors", true);
 ini_set("log_errors", true);
 ini_set("error_log", "../data/logs/setup_errorlog.txt");
@@ -36,15 +36,14 @@ ini_set("error_log", "../data/logs/setup_errorlog.txt");
 header('Content-Type: text/html; charset=UTF-8');
 
 // Check version in the 'first' line, as class.security.php uses
-// PHP5 object syntax not compatible with PHP < 5.2
-if (version_compare(PHP_VERSION, '5.3.0', '<')) {
-    die("You need PHP >= 5.3.0 for ConLite. Sorry, even the setup doesn't work otherwise. Your version: " . PHP_VERSION . "\n");
+if (version_compare(PHP_VERSION, '5.6.0', '<')) {
+    die("You need PHP >= 5.6.0 for ConLite. Sorry, even the setup doesn't work otherwise. Your version: " . PHP_VERSION . "\n");
 }
 
 // Check version
-//PHP >= 5.0.0 and < 6.0.0
-if (version_compare(PHP_VERSION, '7.2.0', '>=')) {
-    die("You need PHP >= 5.3.0  < 7.2.0 for ConLite. Sorry, even the setup doesn't work otherwise. Your version: " . PHP_VERSION . "\n");
+//PHP >= 5.6.0 and < 7.3.0
+if (version_compare(PHP_VERSION, '7.3.0', '>=')) {
+    die("You need PHP >= 5.6.0  < 7.3.0 for ConLite. Sorry, even the setup doesn't work otherwise. Your version: " . PHP_VERSION . "\n");
 }
 
 
@@ -98,6 +97,11 @@ $cfg['path']['frontend'] = CON_FRONTEND_PATH;
 $cfg['path']['conlite'] = $cfg['path']['frontend'] . '/conlite/';
 $cfg['path']['conlite_config'] = CON_FRONTEND_PATH . '/data/config/' . CL_ENVIRONMENT . '/';
 
+// (bool) Flag to use native i18n.
+//        Note: Enabling this could create unwanted side effects, because of
+//        native gettext() behavior.
+$cfg['native_i18n'] = false;
+
 session_start();
 
 // includes