diff --git a/boot.php b/boot.php
index 732816d1b9..779a41f400 100644
--- a/boot.php
+++ b/boot.php
@@ -873,13 +873,10 @@ function get_guid($size = 16, $prefix = "")
 
 /**
  * @brief Used to end the current process, after saving session state.
+ * @deprecated
  */
 function killme()
 {
-	if (!get_app()->is_backend()) {
-		session_write_close();
-	}
-
 	exit();
 }
 
diff --git a/index.php b/index.php
index 2f07fa9af9..af493f2016 100644
--- a/index.php
+++ b/index.php
@@ -12,10 +12,11 @@ use Friendica\App;
 use Friendica\BaseObject;
 use Friendica\Content\Nav;
 use Friendica\Core\Addon;
-use Friendica\Core\System;
-use Friendica\Core\Theme;
 use Friendica\Core\Config;
 use Friendica\Core\L10n;
+use Friendica\Core\Session;
+use Friendica\Core\System;
+use Friendica\Core\Theme;
 use Friendica\Core\Worker;
 use Friendica\Database\DBM;
 use Friendica\Model\Profile;
@@ -77,7 +78,7 @@ if (!$install) {
 		exit();
 	}
 
-	require_once 'include/session.php';
+	Session::init();
 	Addon::loadHooks();
 	Addon::callHooks('init_1');
 
@@ -166,16 +167,16 @@ $a->page['htmlhead'] = '';
 $a->page['end'] = '';
 
 
-if (! x($_SESSION, 'sysmsg')) {
+if (x($_SESSION, 'sysmsg') === false) {
 	$_SESSION['sysmsg'] = [];
 }
 
-if (! x($_SESSION, 'sysmsg_info')) {
+if (x($_SESSION, 'sysmsg_info') === false) {
 	$_SESSION['sysmsg_info'] = [];
 }
 
 // Array for informations about last received items
-if (! x($_SESSION, 'last_updated')) {
+if (x($_SESSION, 'last_updated') === false) {
 	$_SESSION['last_updated'] = [];
 }
 /*
@@ -474,7 +475,7 @@ if (isset($_GET["mode"]) && (($_GET["mode"] == "raw") || ($_GET["mode"] == "mini
 	/// @TODO one day, kill those error-surpressing @ stuff, or PHP should ban it
 	@$doc->loadHTML($content);
 
-	$xpath = new DomXPath($doc);
+	$xpath = new DOMXPath($doc);
 
 	$list = $xpath->query("//*[contains(@id,'tread-wrapper-')]");  /* */