diff --git a/src/Connector/Message.php b/src/Connector/Message.php
index 79fc242..6ba9969 100644
--- a/src/Connector/Message.php
+++ b/src/Connector/Message.php
@@ -179,7 +179,8 @@ public function decodeAttachments(&$parameters)
     private function getSendDateTime(mixed $in): ?\DateTime
     {
         try {
-            $dt = $default = null;
+            $dt = null;
+            $default = null;
             if ((is_int($in) || is_float($in)) && $in > 0) {
                 $dt = new \DateTime("now +{$in} seconds");
             }
@@ -193,10 +194,10 @@ private function getSendDateTime(mixed $in): ?\DateTime
      * Send via the queued job
      * @param string $domain the Mailgun API domain e.g sandboxXXXXXX.mailgun.org
      * @param array $parameters Mailgun API parameters
-     * @param mixed $in
+     * @param mixed $in See:http://php.net/manual/en/datetime.formats.relative.php
      * @return QueuedJobDescriptor|false
      */
-    protected function queueAndSend($domain, $parameters, $in)
+    protected function queueAndSend(string $domain, array $parameters, mixed $in)
     {
         $this->encodeAttachments($parameters);
         $startAfter = null;
@@ -253,7 +254,7 @@ public static function cleanMessageId($message_id): string
      * This is not the "o:deliverytime" option ("Messages can be scheduled for a maximum of 3 days in the future.")
      * To set "deliverytime" set it as an option to setOptions()
      */
-    public function setSendIn(int $seconds)
+    public function setSendIn(int $seconds): static
     {
         $this->send_in_seconds = $seconds;
         return $this;
diff --git a/src/Email/MailgunEmail.php b/src/Email/MailgunEmail.php
index bd4d04b..17342a7 100644
--- a/src/Email/MailgunEmail.php
+++ b/src/Email/MailgunEmail.php
@@ -38,7 +38,7 @@ class MailgunEmail extends TaggableEmail implements EmailWithCustomParameters
      * @var \NSWDPC\Messaging\Mailgun\Connector\Message|null
      * @deprecated
      */
-    private $connector = null;
+    private $connector;
 
     /**
      * Retrieve the connector instance
diff --git a/src/Email/MailgunMailer.php b/src/Email/MailgunMailer.php
index c64a68c..86f9d0f 100644
--- a/src/Email/MailgunMailer.php
+++ b/src/Email/MailgunMailer.php
@@ -64,7 +64,6 @@ public function getAlwaysFrom()
 
     /**
      * Retrieve and set custom parameters on the API connector
-     * @param EmailWithCustomParameters $email
      * @param MessageConnector $connector instance for this send attempt
      */
     protected function assignCustomParameters(EmailWithCustomParameters &$email, MessageConnector &$connector): MessageConnector
@@ -84,16 +83,15 @@ protected function assignCustomParameters(EmailWithCustomParameters &$email, Mes
     /**
      * Taggable: retrieve tags set via setNotificationTags()
      * Doing so will replace any tags assigned through setCustomParameters
-     * @param TaggableEmail $email
      * @param MessageConnector $connector connector instance for this send attempt
-     * @return MessageConnector
      */
     protected function assignNotificationTags(TaggableEmail &$email, MessageConnector &$connector): MessageConnector
     {
         $tags = $email->getNotificationTags();
-        if (empty($tags)) {
+        if ($tags === []) {
             return $connector;
         }
+
         return $connector->setOption('tag', $tags);
     }
 
@@ -147,7 +145,6 @@ public function processEmailDisplayName(array $data): array
 
     /**
      * Given a Swift_Message, prepare parameters for the API send
-     * @param Email $email
      * @return array of parameters for the Mailgun API
      */
     public function prepareParameters(Email $email, MessageConnector $connector): array
diff --git a/tests/MailgunSyncTest.php b/tests/MailgunSyncTest.php
index eb20024..89f0f07 100644
--- a/tests/MailgunSyncTest.php
+++ b/tests/MailgunSyncTest.php
@@ -32,13 +32,18 @@ class MailgunSyncTest extends SapphireTest
 
     protected $test_api_domain = 'testing.example.net';
 
+    // an email address
+    protected $to_address = "test@example.com";
+
+    // optional the recipient name
+    protected $to_name = "Test Tester";
 
-    protected $to_address = "test@example.com";// an email address
-    protected $to_name = "Test Tester";// optional the recipient name
     // Ditto if testing cc
     protected $cc_address = "";
+
     // From header
     protected $from_address = "from@example.com";
+
     protected $from_name = "From Tester";// option the from name (e.g for 'Joe <joe@example.com>' formatting)
     // Test body HTML
     protected $test_body = "<h1>Header provider strategic</h1>"
@@ -168,6 +173,7 @@ public function testMailerDelivery($subject = "test_mailer_delivery", $send_in =
         if ($cc = $this->cc_address) {
             $email->setCc($cc);
         }
+
         $htmlBody = $this->test_body;
         $email->setBody($htmlBody);
 
@@ -360,14 +366,16 @@ public function testAPIDelivery(): void
         Config::modify()->set(Base::class, 'send_via_job', 'no');
 
         $connector = MessageConnector::create();
-        $to = $to_address = $this->to_address;
+        $to = $this->to_address;
+        $to_address = $this->to_address;
         $to_name = $this->to_name;
         if ($to_name) {
             $to = $to_name . ' <' . $to_address . '>';
         }
 
         $this->assertNotEmpty($to_address);
-        $from = $from_address = $this->from_address;
+        $from = $this->from_address;
+        $from_address = $this->from_address;
         $from_name = $this->from_name;
         if ($from_name) {
             $from = $from_name . ' <' . $from_address . '>';
@@ -411,7 +419,7 @@ public function testAPIDelivery(): void
     /**
      * Test that tags can be set via Taggable
      */
-    public function testTaggableEmail()
+    public function testTaggableEmail(): void
     {
         $limit = 3;
 
@@ -443,6 +451,7 @@ public function testTaggableEmail()
         if ($cc = $this->cc_address) {
             $email->setCc($cc);
         }
+
         $email->setBody($this->test_body);
         $tags = ['tagheader1','tagheader2','tagheader3'];
         $email->setNotificationTags($tags);
@@ -542,7 +551,7 @@ public function testSendWithDefaultConfiguration(): void
     /**
      * test a message with attachments
      */
-    public function testAttachmentDelivery()
+    public function testAttachmentDelivery(): void
     {
         $to_address = $this->to_address;
         $to_name = $this->to_name;
@@ -566,6 +575,7 @@ public function testAttachmentDelivery()
         $email->setFrom($from);
         $email->setTo($to);
         $email->setSubject($subject);
+
         $htmlBody = $this->test_body;
         $email->setBody($htmlBody);