If we subscribe to events (or use webhooks) on a project resource, will we get change events for subtasks of tasks in that project?
Yes, subtask events will make their way up their parent hierarchy to the project level. Specifically,
Additionally, change events bubble up - listening to events on a project would include when stories are added to tasks in the project, even on subtasks.
( Events docs)
So even though subtask modifications when querying a project’s tasks with
modified_since doesn’t return tasks which have modified subtasks, it’s possible to follow along in “near-real time” as the changes happen and keep the scanning of a project’s tasks and subtasks to a minimum (just for the case when events or webhooks may have been missed).