My phone is the AT&T Go Phone version of the Lumia 640. I don\’t have my sim card in it yet because I wanted to play around with the OS for a bit before deciding to migrate over. (I\’m currently on Android.) I downloaded the Windows 10 Advisor App and checked for updates but it says I don\’t have an update available. (I was hoping to put Windows 10 on my phone.) Is this because I need to put my SIM card in it and have the phone active on AT&T\’s network to get WM10? I thought I could simply upgrade it to Windows Mobile 10 without having it on a network…is this not true?
At&t has not released windows 10 yet. No you wont need to put in your sim to get the update when they do.