How to select 2G as data network on iOS 8?
It can be found in Settings &gt; Cellular &gt; Voice &amp; Data where in the option is available to select between 2G,3G and LTE.



If the voice option is not available for your iPhone. Please call and check with your respective service/carrier provider.

It's been noted that some of the carrier update for the iOS 8 has removed the "Voice &amp; Data" option because Apple let the carriers to update the cellular settings. It's only a matter of reverting back the update from the service/carrier providers.