Contacts Manager for Lync features four editions, Standard, Enterprise, Corporate, and Ultimate. All edition of Contacts Manager are full-featured but the license key varies based on two limitations only, the number of contact lists you can create, and the number of users you can manage.
The Number of Contact Lists: Based on the edition of your choice, the number of contact lists determines how many contact lists you can create, populate, and update. For example, the Standard edition enables you to create and manage three contact lists only which means you can't create more contact lists.
The Number of Users: The number of users in Contacts Manager for Lync refers to the users to whom you can populate a contact list(s) to. This number does not apply to the number of your Lync users, it is only associated with the number of users that can be managed by Contacts Manager. For example, If you are having 100 Lync users and using the Standard edition which gives you the ability to manage 50 users, you will be able to create a contact list that contains the 100 users but it will be populated to 50 users only.