I just setup a new server with following specs:
Server Information
osTicket Version v1.11 (7b1eee8) — Up to date
Web Server Software Apache/2.4.18 (Ubuntu)
MySQL Version 5.7.25
PHP Version 5.6.39-1+ubuntu16.04.1+deb.sury.org+1

I've got SMTP setup with SASL, no problem there, I can send and I see email flowing in through the email logs.

I setup the osticket email accounts in the 'alises' config and am pointing them to the pipe.php file as instructed.

But now the mail.log is pull these PHP errors:

Remote Server returned '554 5.3.0 < #5.3.0 x-unix; PHP Warning: "continue" targeting switch is equivalent to "break". Did you mean to use "continue 2"? in /var/www/html/osticket/upload/include/class.osticket.php on line 439 PHP Stack trace: 
PHP 1. {main}() /var/www/html/osticket/upload/api/pipe.php:0 
PHP 2. require() /var/www/html/osticket/upload/api/pipe.php:19 
PHP 3. require_once() /var/www/html/osticket/upload/api/api.inc.php:23 
PHP 4. require() /var/www/html/osticket/upload/main.inc.php:23 
PHP Fatal error: Uncaught Error: Call to undefined function mysqli_init() in /var/www/html/osticket/upload/include/mysqli.php:28 Stack trace: #0 /var/www/html/osticket/upload/bootstrap.php(190): db_connect('localhost', 'osticket', 'password', Array) #1 /var/www/html/osticket/upload/main.inc.php(28): Bootstrap::connect() #2 /var/www/html/osticket/upload/api/api.inc.php(23): require_once('/var/www/html/o...') #3 /var/www/html/osticket/upload/api/pipe.php(19): require('/var/www/html/o...') #4 {main} thrown in /var/www/html/osticket/upload/include/mysqli.php on line 28>'

Any ideas? Is this a bug?