From 6b6badad3fdbb554296abdb80a66610de8bc3f6d Mon Sep 17 00:00:00 2001
From: Marcus Bointon <marcus@synchromedia.co.uk>
Date: Tue, 23 Feb 2021 08:59:11 +0100
Subject: [PATCH] Check for mbstring before trying to use it in parseAddresses

---
 changelog.md      | 3 +++
 composer.json     | 2 +-
 src/PHPMailer.php | 2 +-
 3 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/changelog.md b/changelog.md
index 6a107dad..f2f68d8c 100644
--- a/changelog.md
+++ b/changelog.md
@@ -1,5 +1,8 @@
 # PHPMailer Change Log
 
+## WIP
+* Check for mbstring extension before decoding addresss in `parseAddress`
+
 ## Version 6.3.0 (February 19th, 2021)
 * Handle early connection errors such as 421 during connection and EHLO states
 * Switch to Github Actions for CI
diff --git a/composer.json b/composer.json
index 7388bd98..b8aa5cfc 100644
--- a/composer.json
+++ b/composer.json
@@ -40,7 +40,7 @@
         "yoast/phpunit-polyfills": "^0.2.0"
     },
     "suggest": {
-        "ext-mbstring": "Needed to send email in multibyte encoding charset",
+        "ext-mbstring": "Needed to send email in multibyte encoding charset or decode encoded addresses",
         "hayageek/oauth2-yahoo": "Needed for Yahoo XOAUTH2 authentication",
         "league/oauth2-google": "Needed for Google XOAUTH2 authentication",
         "psr/log": "For optional PSR-3 debug logging",
diff --git a/src/PHPMailer.php b/src/PHPMailer.php
index 62553fd4..2103255a 100644
--- a/src/PHPMailer.php
+++ b/src/PHPMailer.php
@@ -1199,7 +1199,7 @@ class PHPMailer
                     )
                 ) {
                     //Decode the name part if it's present and encoded
-                    if (property_exists($address, 'personal') && preg_match('/^=\?.*\?=$/', $address->personal)) {
+                    if (extension_loaded('mbstring') && property_exists($address, 'personal') && preg_match('/^=\?.*\?=$/', $address->personal)) {
                         $address->personal = mb_decode_mimeheader($address->personal);
                     }