The "good story" behind Mailbird licenses has become a cautionary tale for some. Many users who bought "Lifetime" or "Pay Once" licenses for Version 2.0 found themselves locked out when Mailbird 3.0 launched.
Once you have your key, follow these steps to activate the software: Mailbird menu (three horizontal lines in the top-left corner). About Mailbird Activate Mailbird Paste your license key into the field and click Important Note on Security mailbird license key