A post to the Fallen Earth Forums reveals a promotion offering ten days of free access to former subscribers to FALLEN EARTH LLC's post-apocalyptic MMORPG. There's also a subsequent post explaining how to convert your "10 Day Callback Trial" to a full subscription. Here's word on the plan:

We’ve made amazing game enhancements in the past few months and we wanted to call back several of the folks that haven’t had a chance to see these improvements. In an email promotion today, we extended the offer of ten free days of gameplay to some past subscribers and testers so they could experience the changes firsthand.

The promotion was sent to account holders that met one of the following criteria:
    • Those who had not had access to the game in the past 60 days
    • Those who had access but had not logged in to the game in the past 60 days

We are excited to show off what we’ve accomplished and hope that you’ll join us in welcoming these fans back to the Apocalypse.