Mark Shuttleworth said on a number of occasions that the first Ubuntu-powered smartphones should arrive this autumn, but the developers are not yet ready to provide a stable version that can ship so soon. They are now considering building a separate branch of Ubuntu Touch that will get RTM status and that will be focused on stability and bug fixes.
The Ubuntu Touch development has been powering on for the last year and a half, and Canonical has made great progress. The Ubuntu for phones operating system has been separated in a number of branches, and one of them is considered stable.
From time to time, the Ubuntu devs promote an image that passes all the internal tests to the stable branch but, for a mass release of the system, the OS will have to be much better.
That is the reason why the technical lead for the Foundations Team, Colin Watson, made a very interesting proposition regarding a new Ubuntu Touch version that will be designated RTM (release-to-manufacture).
“The Ubuntu phone images are due to hit the release-to-manufacturing (RTM) point later this cycle. With the pace of the phone work, it doesn't look practical to deal with this by SRUing all the required changes into trusty - we're talking about substantial feature development which probably wouldn't be manageable in trusty even with a rather liberal SRU policy for phone-specific components.”
“We don't want to have the phone work interfere too much with other Ubuntu developers, so we need some reasonable way to create a stable branch for RTM, preferably without just hiding everything off in some non-Launchpad repository that would require lots of work in our CI tools to handle,” said Colin Watson on the official mailing list.
In order to make this plan work, a solution has been proposed. The Ubuntu devs should consider using a feature implemented in Launchpad, which didn't really take off, called “derived distributions.” Apparently, it was implemented to allow the branching of an entire distribution or part of it into a new distribution.
There are some problems with this feature and right now it's broken, but the Ubuntu and Launchpad developers will work to fix most of the problems.
If all goes well, the new RTM version to be put together will probably be the most stable and the one that will eventually hit the market. The launch window remains autumn 2014, but it depends on a number of factors. The decision will not rest only in the hands of Canonical, but also in the hands of Bq and Meizu, the two companies that will ship the actual hardware.