diff --git a/src/Content/Conversation.php b/src/Content/Conversation.php
index be7448a336..6d19eb1635 100644
--- a/src/Content/Conversation.php
+++ b/src/Content/Conversation.php
@@ -794,7 +794,7 @@ class Conversation
 			return [];
 		}
 
-		$str_blocked = str_replace(["\n", "\r"], ",", $this->pConfig->get($this->session->getLocalUserId(), 'system', 'blocked'));
+		$str_blocked = str_replace(["\n", "\r"], ",", $this->pConfig->get($this->session->getLocalUserId(), 'system', 'blocked') ?? '');
 		if (empty($str_blocked)) {
 			return [];
 		}
diff --git a/src/Database/Database.php b/src/Database/Database.php
index a34b17adbe..036e6ec2cb 100644
--- a/src/Database/Database.php
+++ b/src/Database/Database.php
@@ -110,7 +110,7 @@ class Database
 		$this->connected = false;
 
 		$port       = 0;
-		$serveraddr = trim($this->configCache->get('database', 'hostname'));
+		$serveraddr = trim($this->configCache->get('database', 'hostname') ?? '');
 		$serverdata = explode(':', $serveraddr);
 		$host       = trim($serverdata[0]);
 		if (count($serverdata) > 1) {
diff --git a/src/Model/Post/Media.php b/src/Model/Post/Media.php
index 04c0db0f80..854e5d8f91 100644
--- a/src/Model/Post/Media.php
+++ b/src/Model/Post/Media.php
@@ -687,7 +687,7 @@ class Media
 				$previews[] = $medium['preview'];
 			}
 
-			$type = explode('/', explode(';', $medium['mimetype'])[0]);
+			$type = explode('/', explode(';', $medium['mimetype'] ?? '')[0]);
 			if (count($type) < 2) {
 				Logger::info('Unknown MimeType', ['type' => $type, 'media' => $medium]);
 				$filetype = 'unkn';
diff --git a/src/Module/Admin/Site.php b/src/Module/Admin/Site.php
index f7fc9d7934..ab6624f776 100644
--- a/src/Module/Admin/Site.php
+++ b/src/Module/Admin/Site.php
@@ -324,8 +324,8 @@ class Site extends BaseAdmin
 		/* Installed langs */
 		$lang_choices = DI::l10n()->getAvailableLanguages();
 
-		if (strlen(DI::config()->get('system', 'directory_submit_url')) &&
-			!strlen(DI::config()->get('system', 'directory'))) {
+		if (DI::config()->get('system', 'directory_submit_url') &&
+			!DI::config()->get('system', 'directory')) {
 			DI::config()->set('system', 'directory', dirname(DI::config()->get('system', 'directory_submit_url')));
 			DI::config()->delete('system', 'directory_submit_url');
 		}
diff --git a/src/Module/Contact/Profile.php b/src/Module/Contact/Profile.php
index b3d0c03733..eadc67818d 100644
--- a/src/Module/Contact/Profile.php
+++ b/src/Module/Contact/Profile.php
@@ -327,7 +327,7 @@ class Profile extends BaseModule
 			'$submit'                    => $this->t('Submit'),
 			'$lbl_info1'                 => $lbl_info1,
 			'$lbl_info2'                 => $this->t('Their personal note'),
-			'$reason'                    => trim($contact['reason']),
+			'$reason'                    => trim($contact['reason'] ?? ''),
 			'$infedit'                   => $this->t('Edit contact notes'),
 			'$common_link'               => 'contact/' . $contact['id'] . '/contacts/common',
 			'$relation_text'             => $relation_text,
diff --git a/src/Module/User/PortableContacts.php b/src/Module/User/PortableContacts.php
index 6629994810..6a3c1201d9 100644
--- a/src/Module/User/PortableContacts.php
+++ b/src/Module/User/PortableContacts.php
@@ -233,7 +233,7 @@ class PortableContacts extends BaseModule
 			}
 
 			if ($selectedFields['tags']) {
-				$tags = str_replace(',', ' ', $contact['keywords']);
+				$tags = str_replace(',', ' ', $contact['keywords'] ?? '');
 				$tags = explode(' ', $tags);
 
 				$cleaned = [];