Mozilla has pushed back its development schedule for Thunderbird 3, the next version of its email client. A planned beta of the package will now be described as a third alpha build.

The first beta of Thunderbird 3 was due to come out at the end of September. It would have been followed by a second in November and a release candidate sometime towards the back end of January, according to a preliminary release schedule. This date is now likely to be pushed back, given that several features are not yet in place, but by how long remains unclear. The cross-platform email client has been available as an alpha for several months.

But the reasons for the change go beyond managing public expectations. Important features including an overhaul of the email client's tabs and calendar integration are not going to make it into the next build. They will feature in the first beta instead.

"While we've been pretty clear for a while that calling something a beta doesn't mean that we're feature-complete, what we've got now feels like it's pretty far from being representative (from a user-experience and user-visible-change point of view) of what Thunderbird 3 is going to feel like," Mosedale writes.

"The confluence of these things together makes us think that we'll do better to ship this as an alpha and not call down the extra attention that a beta will bring just yet."

Mozilla Messaging was established as an offshoot of the Mozilla Foundation in February and sent off into the world with $3m in initial funding. Its goal was to repeat the success of the Firefox web browser in the email and, in future, IM client markets. Up to now the Thunderbird client has lived in Firefox's shadow, but Mozilla hopes to change that by energising developers and end users. ®

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