2G is needed (iOS 11.3 removed it)

Look in:

Settings > General > About > Carrier

for both phones. You'll probably find a newer carrier file on the iOS 11..3 phone. The carriers often provide new carrier files to go with newer versions of iOS. It's up to the carrier to control which modes are allowed by these files.

I'd suggest to the OP that he complain to his provider and tell them to invest more money into it's infastructure. 2G is decommissioned in Canada, and all that converted to LTE. On my provider, there is no option, it's either 3G or LTE. We won't go into technical details.

Also if he has a Carrier File (as in say Ink Machine 33.0), your carrier controls this, not Apple. In my opinion 3G is better than having nothing at all.

This 2G disable option has been pushed from Apple during iOS 11.3 update for iPhone 6 and above Without prior notificactions.

2g toggle option is available for iPhone 5S Users.

3G and 4G signals are light years behind in most small towns and villages in India.

Apple should consider to enable this 2G option during their next update for all iPhone users.

I personally prefer using 2G signals when I am at home and work (Use personal Wifi for internet) this will enhance the iPhone battery life and iPhone performance

Apple controls this. It was there before iOS 11.3 update.

I'm sorry, but that is incorrect. While it may have been there before the iOS 11.3 update, the ability to make cellular selections is controlled by the carrier. The carrier is the one that configures and sends out the carrier file. If you have questions or comments, you need to address that with the carrier, not Apple.

That will not matter to your phone with iOS 11.3. The change is in the carrier file, as I explained earlier, and again is supported here by the post by Malcolm J. Rayfield. It is up to you if you wish to contact your carrier, but they are the one that has made the change.

Apple controls this? Want to provide the proof that it does? Oh wait you can't. That's a violation of the forum rules. Apple does not control this. You have been told so by people who have been here and dealt with this far more and far longer than I have. My phone either has 3G or LTE. That's it and that's with my providers carrier file installed. If I complained even once about this, I would be eaten alive, and not even the bones would be left.

As for your second sentence, it's painfully obvious. Yell at your provider to update it's infastructure. If the spectrum is already saturated, go complain to the Government and get them to auction off more of it. It's also very obvious you don't have Carrier (Band) Aggregation, so we won't go into that.

My provider was mostly Band 4 UMTS (AWS-1) and Band 66 LTE (AWS-3). They bought spectrum (Band 7 (IMT-E) and Band 13 (SMH Upper Block C)) from another provider which the Government of Canada approved. They had 10X10 on the Band 4 UMTS channel. My provider split this off with 5X5 Band 4 LTE and the other 5X5 UMTS.

The third sentence I find extremely amusing, considering you have 1000 GE ES43ACMi locomotives on order, that are part of the Evolution Series Family, and the most technologically advanced AC locomotives on the market (you can thank the ES44AC, ES44DC and ES44C4 for that), yet you're telling me that it's a "market" (2G) that the cell phone carriers can't afford to lose? 2G was decommissioned in Canada. The spectrum for that was repurposed for LTE. You think anyone here has a 2G phone? Maybe in a museum or something. Paperweight, door stop, wheel chock, whatever.

Once again, yell at your provider. You'll eventually get those people off the 2G pipe. Repurpose that for LTE. Not rocket science. See my example above.

The time will come to start either kicking people off 2G or forcing them off. I prefer kicking them off gradually. Your providers cannot afford to have that nonsense carry on indefinitely, especially if you are craving speed.

Of course for you people that have been on here longer than me, you know what to do.

you can request it Feedback - iPhone - Apple