Yes, of course. While there is a cost to repackage and submit the app back through the App Stores, the cost of updating your app will normally be much less than the initial cost of app creation, though this depends on how extensive the update is. One advantage of updating the content of your key is that any new upgrade of the Lucid Mobile platform will also be updated, at no additional cost.
Let the Lucid team know about your update requirements for a quotation.
Once your key has been updated, the app is made available to your existing users via the App Store update process. This is generally a seamless process for end users. The update is automatically installed for those users with auto updating turned on, while for others they are notified of the update via the App Store application.