diff --git a/MatrixConnection.php b/MatrixConnection.php
index f0d8aff..e97a39e 100644
--- a/MatrixConnection.php
+++ b/MatrixConnection.php
@@ -90,8 +90,7 @@ class MatrixConnection
 		return $this->exec_curl_request($handle);
 	}
 
-	function exec_curl_request($handle)
-	{
+	function exec_curl_request($handle) {
 		$response = curl_exec($handle);
 
 		if ($response === false) {
diff --git a/cron.php b/cron.php
index 6140d53..125c487 100644
--- a/cron.php
+++ b/cron.php
@@ -1,6 +1,4 @@
 <?php
-// This file is meant to do tasks that failed on the first attempt
-
 require_once("config.php");
 require_once("mail_templates.php");
 require_once("database.php");
@@ -13,7 +11,6 @@ $sql = "SELECT id, first_name, last_name, username, email, state, note, verify_t
 . " OR state = " . RegisterState::RegistrationDeclined
 . " OR state = " . RegisterState::AllDone . ";";
 foreach ($db->query($sql) as $row) {
-	// will only be executed once
 	$first_name = $row["first_name"];
 	$last_name = $row["last_name"];
 	$username = $row["username"];
diff --git a/functions.php b/functions.php
deleted file mode 100644
index 49d5099..0000000
--- a/functions.php
+++ /dev/null
@@ -1,13 +0,0 @@
-<?php
-function abort($msg="Unknown")
-{
-	header("403 Forbidden");
-	$response = array(
-			"success" => false,
-			"message" => $msg
-			);
-	echo json_encode($response);
-	print("\n");
-	exit();
-}
-?>
diff --git a/lang/lang.de.php b/lang/lang.de-de.php
similarity index 100%
rename from lang/lang.de.php
rename to lang/lang.de-de.php
diff --git a/language.php b/language.php
index 68cdde1..bd50c04 100644
--- a/language.php
+++ b/language.php
@@ -1,7 +1,12 @@
 <?php
-$lang = "de";
+$lang = "de-de";
 if(isset($_GET['lang'])){
-	$lang = $_GET['lang'];
+	$lang = filter_var($_GET['lang'], FILTER_SANITIZE_STRING);
 }
-require_once("lang/lang.".$lang.".php");
+$lang_file = "lang/lang.".$lang.".php";
+if (!file_exists($lang_file)) {
+	throw new Exception("Translation for " . $lang . " not found");
+}
+require_once($lang_file);
+unset($lang_file);
 ?>