diff --git a/application/core/Mail.php b/application/core/Mail.php
index 85a2d0893..7218cd8b3 100644
--- a/application/core/Mail.php
+++ b/application/core/Mail.php
@@ -1,5 +1,8 @@
 <?php
 
+/* Using PHPMailer's namespace */
+use PHPMailer\PHPMailer\PHPMailer;
+
 /**
  * Class Mail
  *
diff --git a/composer.json b/composer.json
index 69b886108..2bbf77d93 100644
--- a/composer.json
+++ b/composer.json
@@ -7,7 +7,7 @@
     "license": "MIT",
     "require-dev": {
         "php": ">=5.5.0",
-        "phpmailer/phpmailer": "~5.2",
+        "phpmailer/phpmailer": "~6.0",
         "gregwar/captcha": "~1.1",
         "phpunit/phpunit": "4.8.*|5.7.*"
     },