Upgrade FusionPBX School Bell

I have a custom School Bell application that works perfectly on FusionPBX 4.x but no longer loads on the 5.x branch. The core job is to refactor whatever needs refactoring so the app installs cleanly and runs just as reliably on FusionPBX 5.x... (Budget: ₹600 - ₹1500 INR, Jobs: API, Database Management, Linux, Lua, MySQL, PHP, Software Development, XML)