Hello!
I am using a Microsoft Lumia 540, just upgraded from Windows Phone 8.1 Denim to Windows 10 Mobile, OS build 10.0.14393.693, firmware 02074.10000.15174.44002.
I upgraded it today, Feb 15th, 2017.
Everything is fine, but the Groove Music app.
I changed my region to US on the phone and on...