AB 28.2 is now on github and the image teams should always have the latest version when they build images. So, when you update your image, you will have latest AB 28.2. In those versions, there is no option for selecting the architecture. This is because you will have the one appropriate to your receiver.
For the benefit of those who do not want to be on latest image, here is the 20160331 version (you must select architecture) which will have the amendments for BBC One HD going to channel 115.