If for any reason, someone is forced to use PHP 5.2 with PHPMailer 5.2.28 and through an office365 account, just set $crypto_method to STREAM_CRYPTO_METHOD_SSLv23_CLIENT.

Works with smtp.office365.com, port 587, SMTPSecure = 'tls'.

Still, you need to have a PHP server which supports TLS v1.2 and (probably) openssl.