Add third party spam filter

How can I add third party paid spam filter on mail-in-a-box. For the information setup is on digital Ocean

If the spam filter is external (like Barracuda or Securence as an example) Simply have the IP your spam filter provider gives you as your MX, and then have your spam filter relay email to and from the miab.

However it’s not a supported feature as MIAB has it’s own spam filter.