Rianu uses Subscriber Lists to sort the subscribers. With Rianu you can create a list for Trial users and trial over.
The subscribers in the Trial users list can get a sequence of emails showing them your SAAS. Then it can also send you alerts to checkin and follow up with the Trial users.
Create Subscriber Lists
To create a subscriber list. Go to Settings.
The subscriber Lists menu will show all the subscriber lists available and the Key which is used by the API.
Enter the new List name and click "Save List" to create a list.