T-Mobile Missing "Cellular Data Network" option and APN settings after iOS 9 update
 

I have a carrier unlocked iPhone. After updating to iOS 9 from 8.4.1, I was prompted to also update the carrier settings. Afterwards, I noticed that when I go Settings > Carrier, it is missing the "Cellular Data Network" option that allows me to configure the APN settings. This option was there...

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Courtesy of WestNet Wireless
www.westnet.ca