How best to trigger a notification upon user completion of a course/module

Problem/Motivation:

We have a need to alert another (non-LRS) system when users complete a course on our Opigno LMS. While I can see some ways to patch this capability into the existing code, the pending release of Opigno 3.1 promises a "complete code optimization", so I assume any patch might not survive the upcoming refactor. What would be the best way to sustainably add in this capability so we can send our notifications both now and in the future with minimal maintenance down the road (Hooks/Events/Rules Integration)? This feature has a bit of urgency, so even ideas that are a little "less sustainable" but that go about adding this feature in a "correct way" would be appreciated!

Thank you!