If you’ve wanted to buy an iPhone but dropped the decision just because it didn’t have a dual-SIM slot, then Apple has answered your prayers. The trio of new iPhones—XS, XS Max and XR—supports two SIM cards.

But any new feature introduced in the iPhone needs to have an “innovation", and the dual-SIM functionality is no different. What this is means is that one SIM slot is a regular one, in which you insert a physical SIM card. The other SIM, however, is an eSIM slot, which allows you to swap network carriers without actually physically swapping the SIMs.

China, however, will have a different version, in which the phone will have two physical SIM slots.

An eSIM, aka “digital SIM" and “virtual SIM", is basically a SIM card that is embedded in the mobile device itself.

If you want to know more about eSIMs, click here.

You can think of it as a blank SIM card that can be changed to a carrier of your choice—without physically replacing the SIM card.

The information on the eSIM can be rewritten by all compliant telecom operators over-the-air. This completely eliminates the need to buy a new physical SIM card while getting a new mobile number.

Currently, only two mobile operators in India support this service — Jio and Airtel. This basically means customers of other telecom operators are cornered into taking a second connection from either Airtel or Jio.

This move has come from Apple mainly to woo customers in emerging markets like India and China, where people prefer having dual-SIMs for various reasons. Experts have often cited the lack of dual-SIM connectivity as one of the reasons why Apple’s phones don’t do as well in such markets.