Since Windows 8 uses XML data format, what are you plans to implement it on
the UPS in the future ? Current supported platforms all use JSON, allowing
to send a notification to everyone from one command. Either you'll lose this
capability, either you'll have to "convert" JSON to XML, which is
problematic since Windows 8 has dozens of XML schemas (and some aren't
really compatible with Apple's one for example).

We are planning on converting json to xml and to be able to have still one message for all devices we try to at least have the main message the same and then add the other things that are windows specific, have a look at this gist:

This is still a work in progress though.