diff --git a/CHANGELOG.md b/CHANGELOG.md
index 544a0fe..bcd528a 100755
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,8 @@
 Changelog
 =========
+1.8.8 (2022-12-11)
+- Fixed bug when `$to` override in the `wp_mail` function
+
 1.8.7 (2022-11-12)
 - Fixed bug when field `Override "From" Details` was not updated
 
diff --git a/includes/wp-mail-api.php b/includes/wp-mail-api.php
index 53cd139..3781235 100644
--- a/includes/wp-mail-api.php
+++ b/includes/wp-mail-api.php
@@ -112,13 +112,6 @@ function mg_mutate_to_rcpt_vars_cb($to_addrs)
 if (!function_exists('wp_mail')) {
     function wp_mail($to, $subject, $message, $headers = '', $attachments = array())
     {
-        // Compact the input, apply the filters, and extract them back out
-        $extractData = apply_filters('wp_mail', compact('to', 'subject', 'message', 'headers', 'attachments'));
-        if (!is_array($extractData)) {
-            $extractData = (array)$extractData;
-        }
-        extract($extractData, EXTR_OVERWRITE);
-
         $mailgun = get_option('mailgun');
         $region = (defined('MAILGUN_REGION') && MAILGUN_REGION) ? MAILGUN_REGION : $mailgun['region'];
         $apiKey = (defined('MAILGUN_APIKEY') && MAILGUN_APIKEY) ? MAILGUN_APIKEY : $mailgun['apiKey'];
@@ -129,10 +122,41 @@ function wp_mail($to, $subject, $message, $headers = '', $attachments = array())
         }
 
         // If a region is not set via defines or through the options page, default to US region.
-        if (!((bool)$region)) {
+        if (!($region)) {
             error_log('[Mailgun] No region configuration was found! Defaulting to US region.');
             $region = 'us';
         }
+        
+        // Respect WordPress core filters
+        $atts = apply_filters( 'wp_mail', compact( 'to', 'subject', 'message', 'headers', 'attachments' ) );
+
+        if ( isset( $atts['to'] ) ) {
+            $to = $atts['to'];
+        }
+
+        if ( ! is_array( $to ) ) {
+            $to = explode( ',', $to );
+        }
+
+        if ( isset( $atts['subject'] ) ) {
+            $subject = $atts['subject'];
+        }
+
+        if ( isset( $atts['message'] ) ) {
+            $message = $atts['message'];
+        }
+
+        if ( isset( $atts['headers'] ) ) {
+            $headers = $atts['headers'];
+        }
+
+        if ( isset( $atts['attachments'] ) ) {
+            $attachments = $atts['attachments'];
+        }
+
+        if (!is_array($attachments)) {
+            $attachments = explode("\n", str_replace("\r\n", "\n", $attachments));
+        }
 
         if (!is_array($attachments)) {
             $attachments = explode("\n", str_replace("\r\n", "\n", $attachments));
@@ -256,7 +280,7 @@ function wp_mail($to, $subject, $message, $headers = '', $attachments = array())
             } elseif (is_array($body['o:tag'])) {
                 $body['o:tag'] = array_merge($body['o:tag'], $tags);
             } else {
-                $body['o:tag'] .= ',' . $tags;
+                $body['o:tag'] .= ',' . implode(',', $tags);
             }
         }
 
diff --git a/mailgun.php b/mailgun.php
index 4cda4c2..2e2342e 100755
--- a/mailgun.php
+++ b/mailgun.php
@@ -3,7 +3,7 @@
  * Plugin Name:  Mailgun
  * Plugin URI:   http://wordpress.org/extend/plugins/mailgun/
  * Description:  Mailgun integration for WordPress
- * Version:      1.8.7
+ * Version:      1.8.8
  * Tested up to: 6.1
  * Author:       Mailgun
  * Author URI:   http://www.mailgun.com/
diff --git a/readme.md b/readme.md
index 8d64a0b..e1172bb 100755
--- a/readme.md
+++ b/readme.md
@@ -5,7 +5,7 @@ Contributors: mailgun, sivel, lookahead.io, m35dev
 Tags: mailgun, smtp, http, api, mail, email
 Requires at least: 3.3
 Tested up to: 6.1
-Stable tag: 1.8.7
+Stable tag: 1.8.8
 Requires PHP: 5.6
 License: GPLv2 or later
 
@@ -130,6 +130,9 @@ MAILGUN_FROM_ADDRESS Type: string
 
 
 == Changelog ==
+= 1.8.8 (2022-12-11): =
+- Fixed bug when `$to` override in the `wp_mail` function
+
 = 1.8.7 (2022-11-12): =
 - Fixed bug when field `Override "From" Details` was not updated
 
diff --git a/readme.txt b/readme.txt
index 6d4629b..991703f 100755
--- a/readme.txt
+++ b/readme.txt
@@ -5,7 +5,7 @@ Contributors: mailgun, sivel, lookahead.io, m35dev
 Tags: mailgun, smtp, http, api, mail, email
 Requires at least: 4.4
 Tested up to: 6.1
-Stable tag: 1.8.7
+Stable tag: 1.8.8
 Requires PHP: 5.6
 License: GPLv2 or later