you can read about it here
http://developer.sonymobile.com/2011/12/07/ice-cream-sandwich-from-source-code-release-to-software-u...
benefit for all consumers worldwide.
Additional approvals might be needed
In some cases, the new and complete software release has to be approved to be used in all the different networks that our phones should work in. Many operators also want to customise the software according to their requirements, which in turn are based on their market, network, differentiation and business model. We implement all of these customisations and create a variety of software packages and releases for each operator.
When all of this is done, we are ready to roll out the software release variants as software upgrades to operators and consumers around the world. The software upgrade can then be downloaded and installed either in the operator’s own update tool (if they have one), from Sony Ericsson’s PC Companion tool, or by over the air updates (FOTA – Firmware Over the Air).
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It should be pointed out that this summary of all the activities and phases is somewhat simplified and is meant to provide a general picture of what we do from the release of the first Ice Cream Sandwich source code, until it is released to our consumers. From Sony Ericsson, we hope it has shed some of light on the work being done for the software upgrades.
If you have any question on this topic, feel free to drop us a line below. We will try to respond as soon as possible. For general software announcements and product information, please check the Sony Ericsson Product Blog regularly.
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unrelated topic, if you have some time please check this thread
http://talk.sonymobile.com/thread/44888
