diff --git a/lib-3rd-party/XLSXWriter.php b/lib-3rd-party/XLSXWriter.php
index 5a649e4d6e..a45263ff3f 100644
--- a/lib-3rd-party/XLSXWriter.php
+++ b/lib-3rd-party/XLSXWriter.php
@@ -230,9 +230,9 @@ class XLSXWriter
       $file->write('<c r="' . $cell . '" s="' . $s . '" t="n"><v>' . self::convert_date_time($value) . '</v></c>');
     } elseif (!is_string($value)) {
       $file->write('<c r="' . $cell . '" s="' . $s . '" t="n"><v>' . ($value * 1) . '</v></c>');//int,float, etc
-    } elseif ($value{0} != '0' && filter_var($value, FILTER_VALIDATE_INT)){ //excel wants to trim leading zeros
+    } elseif ($value[0] != '0' && filter_var($value, FILTER_VALIDATE_INT)){ //excel wants to trim leading zeros
       $file->write('<c r="' . $cell . '" s="' . $s . '" t="n"><v>' . ($value) . '</v></c>');//numeric string
-    } elseif ($value{0} == '='){
+    } elseif ($value[0] == '='){
       $file->write('<c r="' . $cell . '" s="' . $s . '" t="s"><f>' . self::xmlspecialchars($value) . '</f></c>');
     } elseif ($value !== ''){
       $file->write('<c r="' . $cell . '" s="' . $s . '" t="s"><v>' . self::xmlspecialchars($this->setSharedString($value)) . '</v></c>');
diff --git a/lib/Helpscout/Beacon.php b/lib/Helpscout/Beacon.php
index 4371342eba..d208959415 100644
--- a/lib/Helpscout/Beacon.php
+++ b/lib/Helpscout/Beacon.php
@@ -28,7 +28,7 @@ class Beacon {
     $mta = $this->settings->get('mta');
     $currentTheme = WPFunctions::get()->wpGetTheme();
     $currentUser = WPFunctions::get()->wpGetCurrentUser();
-    $sender = $this->settings->get('sender');
+    $sender = $this->settings->get('sender', ['address' => null]);
     $premiumKey = $this->settings->get(Bridge::PREMIUM_KEY_SETTING_NAME) ?: $this->settings->get(Bridge::API_KEY_SETTING_NAME);
     $cronHelper = ContainerWrapper::getInstance()->get(CronHelper::class);
     $cronPingUrl = $cronHelper->getCronUrl(
diff --git a/lib/Tasks/State.php b/lib/Tasks/State.php
index d0f5045511..18a2a6a43b 100644
--- a/lib/Tasks/State.php
+++ b/lib/Tasks/State.php
@@ -95,7 +95,12 @@ class State
           null,
           $queue
         ),
-      ] : null,
+      ] : [
+        'newsletter_id' => null,
+        'queue_id' => null,
+        'subject' => null,
+        'preview_url' => null,
+      ],
     ];
   }
 }
diff --git a/tests/integration/Cron/CronHelperTest.php b/tests/integration/Cron/CronHelperTest.php
index a732dc04ce..0b41682523 100644
--- a/tests/integration/Cron/CronHelperTest.php
+++ b/tests/integration/Cron/CronHelperTest.php
@@ -166,7 +166,6 @@ class CronHelperTest extends \MailPoetTest {
         'run_access' => $time - 4,
         'run_start' => $time - 10,
       ],
-      null,
     ];
     foreach ($testInputs as $testInput) {
       $daemon = $this->getDeamonTestData();
diff --git a/tests/integration/Cron/Workers/SendingQueue/SendingQueueTest.php b/tests/integration/Cron/Workers/SendingQueue/SendingQueueTest.php
index 8660b2bdd3..1554863a32 100644
--- a/tests/integration/Cron/Workers/SendingQueue/SendingQueueTest.php
+++ b/tests/integration/Cron/Workers/SendingQueue/SendingQueueTest.php
@@ -54,6 +54,7 @@ class SendingQueueTest extends \MailPoetTest {
   public $subscriberSegment;
   public $segment;
   public $subscriber;
+  private $mailerTaskDummyResponse = ['response' => true];
   /** @var SendingErrorHandler */
   private $sendingErrorHandler;
   /** @var SettingsController */
@@ -185,7 +186,7 @@ class SendingQueueTest extends \MailPoetTest {
       Stub::make(
         new MailerTask(),
         [
-          'sendBulk' => null,
+          'sendBulk' => $this->mailerTaskDummyResponse,
         ]
       )
     );
@@ -223,7 +224,7 @@ class SendingQueueTest extends \MailPoetTest {
       Stub::make(
         new MailerTask(),
         [
-          'sendBulk' => null,
+          'sendBulk' => $this->mailerTaskDummyResponse,
         ]
       )
     );
@@ -291,7 +292,7 @@ class SendingQueueTest extends \MailPoetTest {
               'subscriber_status' => 'subscribed',
               'subscriber_source' => 'administrator',
             ]);
-            return true;
+            return $this->mailerTaskDummyResponse;
           }),
         ],
         $this
@@ -321,7 +322,7 @@ class SendingQueueTest extends \MailPoetTest {
               'subscriber_status' => 'subscribed',
               'subscriber_source' => 'administrator',
             ]);
-            return true;
+            return $this->mailerTaskDummyResponse;
           }),
         ],
         $this
@@ -344,7 +345,7 @@ class SendingQueueTest extends \MailPoetTest {
             // newsletter body should not be empty
             expect(!empty($newsletter['body']['html']))->true();
             expect(!empty($newsletter['body']['text']))->true();
-            return true;
+            return $this->mailerTaskDummyResponse;
           }),
         ],
         $this
@@ -393,7 +394,7 @@ class SendingQueueTest extends \MailPoetTest {
             // newsletter body should not be empty
             expect(!empty($newsletter[0]['body']['html']))->true();
             expect(!empty($newsletter[0]['body']['text']))->true();
-            return true;
+            return $this->mailerTaskDummyResponse;
           }),
           'getProcessingMethod' => Expected::exactly(1, function() {
             return 'bulk';
@@ -445,7 +446,7 @@ class SendingQueueTest extends \MailPoetTest {
             // newsletter body should not be empty
             expect(!empty($newsletter['body']['html']))->true();
             expect(!empty($newsletter['body']['text']))->true();
-            return true;
+            return $this->mailerTaskDummyResponse;
           }),
         ],
         $this
@@ -522,7 +523,7 @@ class SendingQueueTest extends \MailPoetTest {
             // newsletter body should not be empty
             expect(!empty($newsletter['body']['html']))->true();
             expect(!empty($newsletter['body']['text']))->true();
-            return true;
+            return $this->mailerTaskDummyResponse;
           }),
         ],
         $this
@@ -604,7 +605,7 @@ class SendingQueueTest extends \MailPoetTest {
       new MailerTask(),
       [
         'send' => Expected::exactly(1, function() {
-          return true;
+          return $this->mailerTaskDummyResponse;
         }),
       ],
       $this
@@ -639,7 +640,7 @@ class SendingQueueTest extends \MailPoetTest {
     $sendingQueueWorker = $this->sendingQueueWorker;
     $sendingQueueWorker->mailerTask = Stub::make(
       new MailerTask(),
-      ['send' => true]
+      ['send' => $this->mailerTaskDummyResponse]
     );
     $sendingQueueWorker->process();
 
@@ -660,7 +661,7 @@ class SendingQueueTest extends \MailPoetTest {
     $sendingQueueWorker = $this->sendingQueueWorker;
     $sendingQueueWorker->mailerTask = Stub::make(
       new MailerTask(),
-      ['send' => true]
+      ['send' => $this->mailerTaskDummyResponse]
     );
 
     // newsletter is sent to existing subscriber
@@ -687,7 +688,7 @@ class SendingQueueTest extends \MailPoetTest {
     $sendingQueueWorker = $this->sendingQueueWorker;
     $sendingQueueWorker->mailerTask = Stub::make(
       new MailerTask(),
-      ['send' => true]
+      ['send' => $this->mailerTaskDummyResponse]
     );
 
     // newsletter is not sent to globally unsubscribed subscriber
@@ -705,7 +706,7 @@ class SendingQueueTest extends \MailPoetTest {
     $sendingQueueWorker = $this->sendingQueueWorker;
     $sendingQueueWorker->mailerTask = Stub::make(
       new MailerTask(),
-      ['send' => true]
+      ['send' => $this->mailerTaskDummyResponse]
     );
 
     // newsletter is not sent to subscriber unsubscribed from segment
@@ -723,7 +724,7 @@ class SendingQueueTest extends \MailPoetTest {
     $sendingQueueWorker = $this->sendingQueueWorker;
     $sendingQueueWorker->mailerTask = Stub::make(
       new MailerTask(),
-      ['send' => true]
+      ['send' => $this->mailerTaskDummyResponse]
     );
 
     // newsletter is not sent to inactive subscriber
@@ -762,7 +763,7 @@ class SendingQueueTest extends \MailPoetTest {
       Stub::make(
         new MailerTask(),
         [
-          'sendBulk' => true,
+          'sendBulk' => $this->mailerTaskDummyResponse,
         ]
       )
     );
@@ -799,7 +800,7 @@ class SendingQueueTest extends \MailPoetTest {
       Stub::make(
         new MailerTask(),
         [
-          'send' => Expected::once(),
+          'send' => Expected::once($this->mailerTaskDummyResponse),
         ],
         $this
       )
diff --git a/tests/integration/DynamicSegments/FreePluginConnectors/SubscribersListingsHandlerFactoryTest.php b/tests/integration/DynamicSegments/FreePluginConnectors/SubscribersListingsHandlerFactoryTest.php
index 8b4a0319bb..fa4c87f76f 100644
--- a/tests/integration/DynamicSegments/FreePluginConnectors/SubscribersListingsHandlerFactoryTest.php
+++ b/tests/integration/DynamicSegments/FreePluginConnectors/SubscribersListingsHandlerFactoryTest.php
@@ -13,7 +13,7 @@ class SubscribersListingsHandlerFactoryTest extends \MailPoetTest {
     $segment->name = 'name';
     $segment->type = 'unknown';
     $listings = new SubscribersListingsHandlerFactory();
-    $result = $listings->get($segment, []);
+    $result = $listings->get($segment, ['filter' => ['segment' => null]]);
     expect($result)->null();
   }
 
@@ -24,7 +24,7 @@ class SubscribersListingsHandlerFactoryTest extends \MailPoetTest {
       'type' => DynamicSegment::TYPE_DYNAMIC,
     ]);
     $listings = new SubscribersListingsHandlerFactory();
-    $result = $listings->get($segment, []);
+    $result = $listings->get($segment, ['filter' => ['segment' => null]]);
     expect($result)->notNull();
   }
 
diff --git a/tests/integration/Subscribers/ConfirmationEmailMailerTest.php b/tests/integration/Subscribers/ConfirmationEmailMailerTest.php
index b19446faae..d427e99255 100644
--- a/tests/integration/Subscribers/ConfirmationEmailMailerTest.php
+++ b/tests/integration/Subscribers/ConfirmationEmailMailerTest.php
@@ -128,7 +128,7 @@ class ConfirmationEmailMailerTest extends \MailPoetTest {
 
     $mailer = Stub::makeEmpty(Mailer::class, [
       'send' => function() {
-        return true;
+        return ['response' => true];
       },
     ], $this);
     $sender = new ConfirmationEmailMailer(
@@ -156,7 +156,7 @@ class ConfirmationEmailMailerTest extends \MailPoetTest {
 
     $mailer = Stub::makeEmpty(Mailer::class, [
       'send' => function() {
-        return true;
+        return ['response' => true];
       },
     ], $this);
     $sender = new ConfirmationEmailMailer(