I was about to post asking the same question regarding the firmware on the phones if anyone can answer this; I was going to create a separate thread but this one relates to my question. I have the 99.95 ATT goPhone version of the Lumia 635 (RM-975 VAR NAM US AT&T PREPAID SL - 059V714) I'm assuming also the contract version being 139.95 is identical hardware however it's firmware is RM-975 VAR NAM US AT&T POSTPAID SL - 059W380. Regarding Lumia ROMs on carriers is there any difference between the Prepaid and Postpaid firmware? I'm not too fluent yet in taking WP ROMs apart, i'm new to the WP. Also i'm interested in debranding this phone t strip it off bloatware, I don't use any of the ATT apps or MS ones but i'm not seeing a black firmware (I believe that's correct term) for this phone but again i'm new to this sorta stuff on Windows Phones, used to root and custom rom/debloat stock roms on android but made the switch and I like it so far
Lumia 635 Prepaid Firmware - 01061.00070.14246.29017
Lumia 635 Postpaid Firmware - 01061.00070.14246.29003