With the latest version of Android, dubbed Pie, becoming official on August 6, manufacturers are notifying users regarding Android updates for their phones. Sony announced that their premium phones are due for their Pie Android updates starting November. These are the Xperia XZ2, XZ2 Premium, XZ2 Compact, Xperia XZ Premium, XZ1 and XZ1 Compact. Owners of the XA2, XA2 Ultra and XA2 Plus will have to wait for their Android updates until early 2019.

But why exactly does it take so long for manufacturers to roll out a new version of an OS? Sony has published this infographic below, trying to explain. There’s a lot going on from getting the bits until rolling them out Manufacturers have to adapt the code and make it work on their hardware. They also have to apply their own customization. Then comes testing internally and externally. This is done for every model individually. At the end, users get those lovely notifications for their Android updates.

…and the procedure is even more cumbersome in case of carrier phones, when operators add an extra layer of customization, testing, and roll-out.