One software license is required per user.
MDG Technology products require Sparx Systems Enterprise Architect.

MDG Products do not require a subscription renewal. Provided you have an up to date Enterprise Architect Subscription you will be able to use the latest version of your MDG extension.

Floating License
Floating licenses are suitable for companies who wish to automate the management of Enterprise Architect registration keys, because they can be administered in a single, centralized repository. Sparx Systems Keystore Service provides the repository and administrative software to manage floating licenses.
The floating licenses service also supports off-site usage by allocating a key for a fixed period defined by an administrator.

You will need a floating license for each concurrent user.
For example if you have a team of 10 users but only require 5 users to use Enterprise Architect at any one time then you would need to purchase 5 Floating Licenses.