fixes #1939 update phpmailer from 6.5.1 to 6.8.0 (PHP 8.2 compatibility)

include/phpmailer/POP3.php

@@ -46,7 +46,7 @@ class POP3
      *
      * @var string
      */
-    const VERSION = '6.5.1';
+    const VERSION = '6.8.0';
 
     /**
      * Default POP3 port number.
@@ -308,6 +308,7 @@ class POP3
     {
         if (!$this->connected) {
             $this->setError('Not connected to POP3 server');
+            return false;
         }
         if (empty($username)) {
             $username = $this->username;
@@ -336,7 +337,21 @@ class POP3
      */
     public function disconnect()
     {
-        $this->sendString('QUIT');
+        // If could not connect at all, no need to disconnect
+        if ($this->pop_conn === false) {
+            return;
+        }
+
+        $this->sendString('QUIT' . static::LE);
+
+        // RFC 1939 shows POP3 server sending a +OK response to the QUIT command.
+        // Try to get it.  Ignore any failures here.
+        try {
+            $this->getResponse();
+        } catch (Exception $e) {
+            //Do nothing
+        }
+
         //The QUIT command may cause the daemon to exit, which will kill our connection
         //So ignore errors here
         try {
@@ -344,6 +359,10 @@ class POP3
         } catch (Exception $e) {
             //Do nothing
         }
+
+        // Clean up attributes.
+        $this->connected = false;
+        $this->pop_conn  = false;
     }
 
     /**