Now that AT&T and Verizon have switched on their support for eSIMs in iPhones, it's T-Mobile's turn. The magenta network has released an eSIM app that adds a line to your iPhone XR, iPhone XS or iPhone XS Max without making you insert a little card. There's one big gotcha, though: it's currently limited to prepaid service. T-Mobile pitches this as an option for visitors to the US, existing customers who want a secondary line or would-be switchers who want to try the network without a deeper commitment. Support for regular subscriptions is coming, but you'll presently need to hold off if you wanted to reserve the physical slot for travel SIMs or (gasp) a rival provider.