When a new Framework is released, often packages are updated to take advantage of the new framework. When a device without the new framework requests available package updates, these new packages are included in the results, but trying to install them results in an error. The same applies where an updated package no longer supports the device's architecture.
Part of this is server-side: the returned updates should be filtered based on the architecture of, and frameworks available on the device. But in order for the server to know which frameworks are available, the client needs to send them. In unity-scope-click, this data is sent in the X-Ubuntu-Architecture and X-Ubuntu-Frameworks headers [0]. It would be nice if we could do the same from the update manager, for consistency. It should also send an Accept header with the value application/json.
I think this would need to be added to the system-update plugin's network component [1].
[0] https://wiki.ubuntu.com/AppStore/Interfaces/ClickPackageIndex#Client_Platform_Properties
[1] http://bazaar.launchpad.net/~system-settings-touch/ubuntu-system-settings/trunk/view/head:/plugins/system-update/network/network.cpp#L42
There is some thought of creating a shared service for this to replace the two current implementations.