We do not have a free version of Mailbird at the moment.
We completely understand that our paid version might not be the best solution for people that enjoy free apps.
Over several years, we've learned that paid version of Mailbird, has helped people get organized, manage emails faster and with a really enjoyable experience. To continue using it and enjoy all the features you need to purchase a license.
Here's you can get one: https://www.getmailbird.com/pricing/
Download Mailbird for free here