The initial focus will be on the development of Thunderbird 3 which the company said will deliver significant improvements including integrated calendaring, better search and enhancements to the overall user experience.
Mozilla Messaging is staffed by a small product development team which will work as part of a community of contributors from around the world.
"We are excited to renew the focus of our open source community on the future of Thunderbird," said David Ascher, chief executive at Mozilla Messaging.
"Every one of us is committed to building a great email product that people will love to use and that serves as the foundation for choice in a critical area of internet software."
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