The Premium plan is designed for businesses that have scaled up a bit already and will have typically 5 to 15 users, and several numbers in various countries or for various teams. It opens webhooks and integrations to connect Aircall with your other business calls, along with analytics to make sure you deliver an awesome support.
The Entreprise plan is designed for established businesses with large support teams and/or presence in multiple places. Use this plan as well if you'd like to manage easily all your business lines (team and personal lines). It opens custom analytics and integrations so you can improve your productivity and monitoring as much as you'd like.
On both plan, a minimum of three users is required.