diff --git a/src/Module/Api/Friendica/Activity.php b/src/Module/Api/Friendica/Activity.php
index 70aeee613..3915c2089 100644
--- a/src/Module/Api/Friendica/Activity.php
+++ b/src/Module/Api/Friendica/Activity.php
@@ -52,7 +52,7 @@ class Activity extends BaseApi
 		$res = Item::performActivity($request['id'], $this->parameters['verb'], $uid);
 
 		if ($res) {
-			if (!empty($this->parameters['extension']) && ($this->parameters['extension'] == 'xml')) {
+			if ($this->parameters['extension'] ?? '' == 'xml') {
 				$ok = 'true';
 			} else {
 				$ok = 'ok';
diff --git a/src/Module/Api/Friendica/Notification.php b/src/Module/Api/Friendica/Notification.php
index 1f5ac9b48..d16e0e2b0 100644
--- a/src/Module/Api/Friendica/Notification.php
+++ b/src/Module/Api/Friendica/Notification.php
@@ -43,7 +43,7 @@ class Notification extends BaseApi
 			$notifications[] = new ApiNotification($Notify);
 		}
 
-		if (!empty($this->parameters['extension']) && ($this->parameters['extension'] == 'xml')) {
+		if ($this->parameters['extension'] ?? '' == 'xml') {
 			$xmlnotes = [];
 			foreach ($notifications as $notification) {
 				$xmlnotes[] = ['@attributes' => $notification->toArray()];
diff --git a/src/Module/Api/Friendica/Profile/Show.php b/src/Module/Api/Friendica/Profile/Show.php
index 60f4f024b..2507b7e27 100644
--- a/src/Module/Api/Friendica/Profile/Show.php
+++ b/src/Module/Api/Friendica/Profile/Show.php
@@ -48,7 +48,7 @@ class Show extends BaseApi
 		$profile = self::formatProfile($profile, $profileFields);
 
 		$profiles = [];
-		if (!empty($this->parameters['extension']) && ($this->parameters['extension'] == 'xml')) {
+		if ($this->parameters['extension'] ?? '' == 'xml') {
 			$profiles['0:profile'] = $profile;
 		} else {
 			$profiles[] = $profile;
diff --git a/src/Module/Api/GNUSocial/Help/Test.php b/src/Module/Api/GNUSocial/Help/Test.php
index 4cfeda6ab..44a31ba88 100644
--- a/src/Module/Api/GNUSocial/Help/Test.php
+++ b/src/Module/Api/GNUSocial/Help/Test.php
@@ -31,7 +31,7 @@ class Test extends BaseApi
 {
 	protected function rawContent(array $request = [])
 	{
-		if (!empty($this->parameters['extension']) && ($this->parameters['extension'] == 'xml')) {
+		if ($this->parameters['extension'] ?? '' == 'xml') {
 			$ok = 'true';
 		} else {
 			$ok = 'ok';
diff --git a/src/Module/Api/Twitter/Account/RateLimitStatus.php b/src/Module/Api/Twitter/Account/RateLimitStatus.php
index 7a48f4f0e..60cee6ce3 100644
--- a/src/Module/Api/Twitter/Account/RateLimitStatus.php
+++ b/src/Module/Api/Twitter/Account/RateLimitStatus.php
@@ -31,7 +31,7 @@ class RateLimitStatus extends BaseApi
 {
 	protected function rawContent(array $request = [])
 	{
-		if (!empty($this->parameters['extension']) && ($this->parameters['extension'] == 'xml')) {
+		if ($this->parameters['extension'] ?? '' == 'xml') {
 			$hash = [
 				'remaining-hits'        => '150',
 				'@attributes'           => ["type" => "integer"],