I started using this plugin back in the olds days as it was named Wysija 🙂
After upgrading/converting to MailPoet I reached free version 3 of the MailPoet plugin.
Yesterday I changed the plan to Premium version.

It is really a great thing the developers granted to change for free to Premium; thank you for that!

Throughout the years I never had the feeling or need to end up this service and to change to another plugin.