Upgrading to 1.16.1

I have an instance of osTicket version 1.12 and would like to upgrade to 1.16.

I read that version 1.16 requires PHP 8, so that's already on my radar to also upgrade.

Aside from the PHP requirement, can I upgrade directly from 1.12 to 1.16, or do I need to follow a iterative upgrade path?

You should be good to upgrade once you upgrade PHP.