Dual SIM mobiles are largely popular in countries like India and China. A large number of mobile users prefer having two SIM cards, one to attend work and another for personal calls. There are also a large number of companies which provide dual SIM mobile phones and some even providing triple SIM mobiles. Almost every other company has a dual-SIM mobile.
There were rumours that the iPhone 7 released end of last year would be a dual-SIM model and have a 3.5mm headphone jack. However, both the claims were proved false when it was released.
Currently, documents filed with China’s State Intellectual Property Office by Apple describes a dual-SIM card feature allowing iPhones to store two phone numbers. This application seems to have been filed in March 2016 last year and was published in September 2016. The inventor is also listed in the filing named, Li Su. She is the principle architect for cellular software at Apple.
There has also been a patent awarded for a dual SIM card technology in the United Sates in December 2016. Li Su has been listed on this patent too along with two other cellular engineers, Ming Hu and Guojie Dong.
A dual-SIM mobile would get a bit bulkier but Apple might be looking at a SIM less option or an embedded SIM also called an eSIM which can be reprogrammed using software when a person changes their network provider or their number. Apple already has the eSIM on it 9.7 iPad Pro which was released last year.
However, a dual-SIM mobile would be a lot of trouble in countries like Japan, US, Western Europe, South Korea and Australia. Apple exclusively deals with carriers to sell their phones and a dual-SIM might mean a customer may want to use a secondary number from another carrier in which case both Apple and the carrier has to either completely relook at the contract or avoid selling dual-SIM models.