Vodafone explains the process of a firmware update
Using the Huawei Ascend G300 as an example, Vodafone says that once the manufacturer makes the decision to proceed with the update, it waits for the software from the developer, in this case it would be Google. Once the software is received, the OEM develops a version of it for their device. Vodafone, at this point, makes sure that the software includes the features it wants its customers to enjoy and adds branding and features like "music, apps or even remote diagnostics capabilities". The carrier wants its customers to "get the best possible experience" from the moment they turn on their new phone for the first time.
Vodafone engineers are always testing software updates and in most cases, there are quite a few builds before the best one is found. Vodafone's head of terminals technology Chris May says this testing can take from one day to one week depending on previous experiences with the manufacturer and the size of the update. May says security updates and bug fixes are the easiest to put through with platform upgrades being the hardest. That has been seen in the troubles many carriers have had getting Android 4.0 updated on certain models. Sometimes Vodafone can get by with limited testing. IT Technical Manager Kevin Ralph notes that the testing includes data, apps, battery life,etc. But if they are working with a device they have seen before, they won't go back and test the antenna, for example. With the Android 4.0 update for the HuaweiG300, the engineers are conducting a full range of tests since it is the first time they have seen Ice Cream Sandwich running a Huawei device. Most testing is a two-stage process with the carrier reporting back any problems to its suppliers for improvements so that the final update meets Vodafone's highest standards for its customers. After it is approved by the carrier, the update is sent back to the software developer, in this case Google, for approval..
suggesting that the phone's owner use Wi-Fi for the update if it is OTA. As far as determining when the update will actually be released, a date is discussed during the early stages of the process according to Vodafone. The goal is to avoid too many updates for a specific model in a short period of time.
Once testing is done, Vodafone tries to get the update through the remaining process quickly so that its customers have it in their hands as quickly as possible. Now that you've read about the complexity of the process, perhaps you will be a bit more patient while waiting for the next platform update. And for those who miss out on a major OS update like owners of the HTC Desire HD, now you will understand the reasoning behind the decision to leave a phone running on an older build. source: Vodafone via Engadget