Visit https://www.mathworks.com/mwaccount/ and look under "Option". If it says "Designated Computer" then anyone logged into the computer directly at its console can use the license (so, any one person at a time.) If it says "Individual" then the license is tied to a particular username.
You can purchase Software Maintenance Service (SMS). During the period of your SMS contract, you are automatically entitled to any new releases. "Discounts on new releases" are typically handled by having the person back-purchase SMS, though there is a limit on how far back this is permitted.
