I've only just joined the forum and found this thread.
From what I understand SoftPauer used to develop and maintain the official Formula One app on Windows phone but now Formula One Digital Media Limited have taken over responsibility for developing the official F1 mobile app. When they took on the responsibility for the development of the app they discontinued it for Windows Phone.
It's a real shame because the official app gives you live timing and live track positions so you can see them moving around the track
I sent them an email to ask if they have any plans for Windows Phone in the future and their response was;
"Thank for your email.
A Windows Phone version is under discussion for 2015 Race 1.
I will also add your vote to the Win Phone list."
I suggest everyone interested in an official F1 app for windows phone also send an email (fodm[at]fomltd[dot]com) expressing your interest
Being new to the forum I can't post direct links hence the disguised email
cheers 'n gone