Why can't i get the Preview For Developers Update on my HTC 8XT for Sprint?

[Windows Central Question]

When i downloaded the app off the store it downloaded and when i run the app everything seems to be operating normal but after i sign into my developer account, it says to check the enable box and i do and the "Success" Screen appears telling me to go to settings> Phone update. But the problem is, there is no update available! I've tried this app with a Nokia 928 and a Samsung Galaxy ATIV running verizon, and both were successful, how come it isn't working for this phone?

 

[GrandGerminator]

Maybe there's simply no DP preview version available for your phones ?