Q: How do I use 2g on iOS 8?

This is a network dependent hassle, I was in Kolkata and was using Reliance GSM and I very much had the 2g/3g/lte toggle option on the iphone 5s working on i0s8.1, but the moment I inserted my airtel sim the option went away... Seems like Airtel and Vodafone have registered as LTE operators with Apple and hence the SMART ios8 is automatically enabling or disabling the options basis the SIM you are using. This must be immediately removed.

HOUSTON, WE HAVE A TROUBLE AGAIN:

I have dealed with this problem from ios 7, and now ios 8.0 - ios 8,1 beta and finaly ios 8.1
First i lost 2G button, then i get 2G, 3G and LTE button.

In 2 weeks this work for me. Yesterday a "carrier settings" arrive my phone (iphone5). I pushed "ok" buton to upgrade, and 2 seconds after i have same trouble again. Now im back to no 2G, only 3G and LTE. My carrier have this month opened for 4G/LTE to all customers. I think thats the reason.
Now i speaked to topp boss in company today, and he says this is Apple`s problem, and he says that this carrier update comes from Apple, and not "Telenor".

My question is; who send out "carrier update", Apple, or Telenor as is my phone company?
And what to do now?

Carrier updates come from the carrier, not Apple.  Period