The company isn't killing --it will continue to support the email client, it just won't be innovating for the program.

"We have come to the conclusion that continued innovation on Thunderbird is not the best use of our resources given our ambitious organizational goals," Thunderbird Managing Director Jb Piacintino wrote in an internal letter sent to Mozilla employees Friday. The letter was .

"We're not 'stopping' Thunderbird," Piacintino wrote. "But proposing we adapt the Thunderbird release and governance model in a way that allows both ongoing security and stability maintenance, as well as community-driven innovation and development for the project.

Piacintino went on to explain that the official word on Thunderbird's fate will come in a blog post by Mozilla Foundation Chair Mitch Baker on Monday. The shift in development emphasis on Thunderbird means some of the staff will be shifted to other projects, a process that TechCrunch notes has been going on since January.

Mozilla , which included Thunderbird, into its Mozilla Labs group in April. There the email program was to be on a development track alongside another group working on online communications and social interactions on the web, but it was clear that Mozilla was reassessing the role of the program in its future plans.