Is it possible to add or update people (subscribers) in a calendar event in Basecamp new API?
In a documentation https://github.com/basecamp/bcx-api/blob/master/sections/calendar_events.md are only these parameters:
{
"summary": "My all-day event spanning two days",
"description": "Details to follow",
"all_day": true,
"starts_at": "2012-03-28",
"ends_at": "2012-03-30"
}