Anthony Ngyuyen created his own Windows Phone 8.1 compatible app that can
talk to the nRF8001 UART. via github
Open Source, Windows Phone app that supports nRF UART
Connect to Bluetooth low energy (Bluetooth Smart) devices running the custom Nordic Semiconductor UART service.
UUIDs used are:
6E400001-B5A3-F393-E0A9-E50E24DCCA9E for the Service
6E400002-B5A3-F393-E0A9-E50E24DCCA9E for the TX Characteristic Property = Notify
6E400003-B5A3-F393-E0A9-E50E24DCCA9E for the RX Characteristic Property = Write without response