What is the difference between the User, Enterprise and Platinum license?

The User license is an individual license. There must be a valid license for each individual who will have access to the software (just like a “Named User License”).
The Enterprise license grants you the right to use Remote Desktop Manager for up to 50 employees for a single site (location). Remote workers that are based in another office are NOT included in the license. A location is a place of work – if you are at another address, you will need another license.
The Platinum license grants you the right to use Remote Desktop Manager for more than 50 employees (51 users and up), across multiple sites (offices) worldwide. You will receive 1 license key covering your total number of seats, 1 seat per named user.