Can I change my subscription plan to use more devices?

Yes. $US1 per additional device.

In Dante Director as the account Administrator, you can access the FastSpring Portal from Settings > Manage Subscription, by clicking on “Manage Plan’

In the FastSpring Portal, Subscriptions tab, select ‘Manage > Modify Subscription’

Note, you can only modify the subscription once you are past the trial period, or if you choose ‘Pay Today’.