Me too facing this problem...I am running Cyan + update 1 in my 720. Just when I wanted to customize my xbox avatar, I found Xbox live Extras application is no more available for me.
Is there anyone facing the same issue? Is this because of the running OS on my device?
Not sure do you mean you can't find the app on your phone or marketplace?
I'm on the same version of os and have it still. Having said that I haven't done any factory or hard resets which would have got rid if it.
I just updated to DP update 1 after getting CYAN. I remember I could use it earlier but now when I go to the store, it says not available. I can see it but its not downloadable..
guess its OS issue.