iPhone 12 5G support document leak has bad news for some users

All of the newer iPhone models starting with the iPhone XS feature Dual SIM, a special mode that takes advantage of both the nano-SIM slot and eSIM to give users access to two different lines. This feature is particularly useful for consumers who frequently travel or who need a separate business line, but it seems there will be one big limitation: the mode isn't compatible with 5G.

The iPhone's Dual SIM mode can, put simply, be used to have two phone numbers on a single smartphone without having to use a shady third-party app service. The feature is available to users who are using wireless service with support for eSIM; Apple notes on its support website that you can use two different carriers only if your iPhone is unlocked.

A Redditor recently asked a question about the iPhone 12's Dual SIM mode and 5G on Reddit, where it was asked whether the Dual SIM, Dual Standby mode will be able to use 5G networks. A different user going by the handle "ctthrow1" responded with a screenshot of an internal Apple document intended for distribution to wireless carriers and retailers.

In the document, which MacRumors claims to have verified as authentic, Apple notes that the iPhone 12 Dual SIM mode does not support 5G and will instead bump users down to 4G LTE. The full section from the leaked document reads:

Does 5G work with Dual SIM?

When using two lines in Dual SIM mode, 5G data isn't supported on either line and will fall back to 4G LTE. If customers are using eSIM only and are on a 5G-supported carrier and service plan, they'll have 5G access.

This isn't all bad news, however — MacRumors claims that in the materials it viewed, Apple will enable 5G support for Dual SIM mode via a software update scheduled for release later this year. Until then, iPhone 12 users on eSIM will need to remove the nano-SIM from their handset to access 5G.