In the activity settings you can turn on or off Allow Users to Relate Multiple Contacts to Tasks and Events. But how can I check this in my Apex code? I thought it might be in the Organization table but I dont see anything there.
The last checkbox in the list is called
Allow Users to Relate Multiple Contacts to Tasks and Events. Helptext:
Enabling this feature lets users relate up to 50 contacts to a task or event (except a recurring task or event).
Apex, you can inspect the global describe to see if a specific
sObjectType is supported:
Boolean isTaskRelationEnabled = Schema.getGlobalDescribe().containsKey('TaskRelation');