diff --git a/src/Model/Item.php b/src/Model/Item.php
index 1e3326e285..5144e73e0e 100644
--- a/src/Model/Item.php
+++ b/src/Model/Item.php
@@ -1841,13 +1841,13 @@ class Item
 		$parsed = parse_url($uri);
 
 		// Remove the scheme to make sure that "https" and "http" doesn't make a difference
-		unset($parsed["scheme"]);
+		unset($parsed['scheme']);
 
 		// Glue it together to be able to make a hash from it
-		$host_id = implode("/", $parsed);
+		$host_id = implode('/', $parsed);
 
 		// Use a mixture of several hashes to provide some GUID like experience
-		return hash("crc32", $host) . '-'. hash('joaat', $host_id) . '-'. hash('fnv164', $host_id);
+		return hash('crc32', $host) . '-'. hash('joaat', $host_id) . '-'. hash('fnv164', $host_id);
 	}
 
 	/**
@@ -1859,9 +1859,9 @@ class Item
 	 * @return string
 	 * @throws \Friendica\Network\HTTPException\InternalServerErrorException
 	 */
-	public static function newURI($uid, $guid = "")
+	public static function newURI(int $uid, string $guid = ''): string
 	{
-		if ($guid == "") {
+		if ($guid == '') {
 			$guid = System::createUUID();
 		}
 
diff --git a/src/Protocol/ActivityPub/Receiver.php b/src/Protocol/ActivityPub/Receiver.php
index be1c3b7e7c..29f6b5bec7 100644
--- a/src/Protocol/ActivityPub/Receiver.php
+++ b/src/Protocol/ActivityPub/Receiver.php
@@ -80,13 +80,12 @@ class Receiver
 	/**
 	 * Checks incoming message from the inbox
 	 *
-	 * @param         $body
-	 * @param         $header
+	 * @param string  $body Body string
+	 * @param array   $header Header lines
 	 * @param integer $uid User ID
 	 * @throws \Exception
-	 * @todo Find type for $body/$header
 	 */
-	public static function processInbox($body, $header, int $uid)
+	public static function processInbox(string $body, array $header, int $uid)
 	{
 		$activity = json_decode($body, true);
 		if (empty($activity)) {
@@ -98,7 +97,7 @@ class Receiver
 
 		$actor = JsonLD::fetchElement($ldactivity, 'as:actor', '@id');
 
-		$apcontact = APContact::getByURL($actor);
+		$apcontact = APContact::getByURL($actor ?? '');
 		if (empty($apcontact)) {
 			Logger::notice('Unable to retrieve AP contact for actor - message is discarded', ['actor' => $actor]);
 			return;