diff --git a/includes/admin.php b/includes/admin.php
index 8e4c047..fa79c9b 100755
--- a/includes/admin.php
+++ b/includes/admin.php
@@ -29,7 +29,7 @@ class MailgunAdmin extends Mailgun {
     /**
      * @var array
      */
-    protected array $options = array();
+    protected array $options = [];
 
     /**
      * @var string $hook_suffix
diff --git a/includes/mg-filter.php b/includes/mg-filter.php
index fdf216b..b63283e 100755
--- a/includes/mg-filter.php
+++ b/includes/mg-filter.php
@@ -162,7 +162,7 @@ function mg_detect_from_address( $from_addr_header = null ): string {
             'wp_mail_from',
             $from_addr
         );
-        if ( ! is_null($filter_from_addr) || ! empty($filter_from_addr)) {
+        if (!is_null($filter_from_addr)) {
             $from_addr = $filter_from_addr;
         }
     }
@@ -193,9 +193,9 @@ function mg_detect_from_address( $from_addr_header = null ): string {
  *
  * @since    1.5.8
  */
-function mg_parse_headers( $headers = array() ): array {
+function mg_parse_headers( $headers = []): array {
     if (empty($headers)) {
-        return array();
+        return [];
     }
 
     if ( ! is_array($headers)) {
@@ -204,7 +204,7 @@ function mg_parse_headers( $headers = array() ): array {
         $tmp = $headers;
     }
 
-    $new_headers = array();
+    $new_headers = [];
     if ( ! empty($tmp)) {
         $name     = null;
         $value    = null;
@@ -232,7 +232,7 @@ function mg_parse_headers( $headers = array() ): array {
             $value = trim($value);
 
             if ( ! isset($new_headers[ $name ])) {
-                $new_headers[ $name ] = array();
+                $new_headers[ $name ] = [];
             }
 
             $new_headers[ $name ][] = array(
@@ -264,7 +264,7 @@ function mg_dump_headers( array $headers = null ): string {
     $header_string = '';
     foreach ($headers as $name => $values) {
         $header_string .= sprintf('%s: ', $name);
-        $header_values  = array();
+        $header_values  = [];
 
         foreach ($values as $content) {
             // XXX - Is it actually okay to discard `parts` and `boundary`?
diff --git a/includes/wp-mail-api.php b/includes/wp-mail-api.php
index 2d910a1..eefce07 100644
--- a/includes/wp-mail-api.php
+++ b/includes/wp-mail-api.php
@@ -71,7 +71,7 @@ function mg_mutate_to_rcpt_vars_cb( $to_addrs ): array {
     }
 
     if (has_filter('mg_use_recipient_vars_syntax')) {
-        $rcpt_vars     = array();
+        $rcpt_vars     = [];
         $use_rcpt_vars = apply_filters('mg_use_recipient_vars_syntax', null);
         if ($use_rcpt_vars) {
 
@@ -122,7 +122,7 @@ function mg_mutate_to_rcpt_vars_cb( $to_addrs ): array {
      * @return bool
      * @throws \PHPMailer\PHPMailer\Exception
      */
-    function wp_mail( $to, $subject, $message, $headers = '', $attachments = array() ) {
+    function wp_mail( $to, $subject, $message, $headers = '', $attachments = []) {
         $mailgun = get_option('mailgun');
         $region  = ( defined('MAILGUN_REGION') && MAILGUN_REGION ) ? MAILGUN_REGION : $mailgun['region'];
         $apiKey  = ( defined('MAILGUN_APIKEY') && MAILGUN_APIKEY ) ? MAILGUN_APIKEY : $mailgun['apiKey'];
@@ -169,12 +169,12 @@ function wp_mail( $to, $subject, $message, $headers = '', $attachments = array()
             $attachments = explode("\n", str_replace("\r\n", "\n", $attachments));
         }
 
-        $cc  = array();
-        $bcc = array();
+        $cc  = [];
+        $bcc = [];
 
         // Headers
         if (empty($headers)) {
-            $headers = array();
+            $headers = [];
         } else {
             if ( ! is_array($headers)) {
                 // Explode the headers out, so this function can take both
@@ -183,9 +183,9 @@ function wp_mail( $to, $subject, $message, $headers = '', $attachments = array()
             } else {
                 $tempheaders = $headers;
             }
-            $headers = array();
-            $cc      = array();
-            $bcc     = array();
+            $headers = [];
+            $cc      = [];
+            $bcc     = [];
 
             // If it's actually got contents
             if ( ! empty($tempheaders)) {
@@ -273,7 +273,7 @@ function wp_mail( $to, $subject, $message, $headers = '', $attachments = array()
             $body['recipient-variables'] = $rcpt_data['rcpt_vars'];
         }
 
-        $body['o:tag'] = array();
+        $body['o:tag'] = [];
         if (defined('MAILGUN_TRACK_CLICKS')) {
             $trackClicks = MAILGUN_TRACK_CLICKS;
         } else {
diff --git a/mailgun.php b/mailgun.php
index 6bc65b4..29cd231 100755
--- a/mailgun.php
+++ b/mailgun.php
@@ -3,9 +3,9 @@
  * Plugin Name:  Mailgun
  * Plugin URI:   http://wordpress.org/extend/plugins/mailgun/
  * Description:  Mailgun integration for WordPress
- * Version:      2.1.9
+ * Version:      2.1.10
  * Requires PHP: 7.4
- * Requires at least: 4.4
+ * Requires at least: 5.6
  * Author:       Mailgun
  * Author URI:   http://www.mailgun.com/
  * License:      GPLv2 or later
@@ -213,7 +213,7 @@ public function deactivate_and_die( $file ): void {
      *
      * @return    string
      */
-    public function api_call( string $uri, array $params = array(), string $method = 'POST' ): string {
+    public function api_call( string $uri, array $params = [], string $method = 'POST' ): string {
         $options   = get_option( 'mailgun' );
         $getRegion = ( defined( 'MAILGUN_REGION' ) && MAILGUN_REGION ) ? MAILGUN_REGION : $options['region'];
         $apiKey    = ( defined( 'MAILGUN_APIKEY' ) && MAILGUN_APIKEY ) ? MAILGUN_APIKEY : $options['apiKey'];
@@ -369,7 +369,7 @@ public function add_list(): void {
      * @param array  $args widget arguments
      * @throws JsonException
      */
-    public function list_form( string $list_address, array $args = array() ): void {
+    public function list_form( string $list_address, array $args = []): void {
         $widgetId        = $args['widget_id'] ?? 0;
         $widget_class_id = "mailgun-list-widget-{$widgetId}";
         $form_class_id   = "list-form-{$widgetId}";
diff --git a/readme.md b/readme.md
index 78c0a5b..4e2e873 100755
--- a/readme.md
+++ b/readme.md
@@ -4,7 +4,7 @@ Mailgun for WordPress
 Contributors: mailgun, sivel, lookahead.io, m35dev, alanfuller
 Tags: mailgun, smtp, http, api, mail, email
 Tested up to: 6.8.1
-Stable tag: 2.1.9
+Stable tag: 2.1.10
 Requires PHP: 7.4
 License: GPLv2 or later
 
diff --git a/readme.txt b/readme.txt
index 1c12f27..3dcccf6 100755
--- a/readme.txt
+++ b/readme.txt
@@ -4,7 +4,7 @@ Mailgun for WordPress
 Contributors: mailgun, sivel, lookahead.io, m35dev, alanfuller
 Tags: mailgun, smtp, http, api, mail, email
 Tested up to: 6.8.1
-Stable tag: 2.1.9
+Stable tag: 2.1.10
 Requires PHP: 7.4
 License: GPLv2 or later