iPhone sales might fall if Apple fails to introduce a 5G variant. That's the opinion of a report from analyst IDC.

It says that the rest of 2019 "could be challenging" for Apple if there's no 5G iPhone but that if there is a 5G model last year then sales will pick up again (that latter part sounds like a bit of a no brainer). 

We've known for some time that we're probably not going to get a 5G iPhone until 2020 - but we think it's entirely possible that an iPhone 5G could land before next September. 

IDC believes iPhone shipments are expected to fall by 15 percent to 177.9 million this yer, yet and believes Android's market share to grow from 85 percent to 87 percent this year (yes it is that much) due to "a push from the new devices."

"We don't think 5G will be the saviour in smartphones, but we do see it as a critical evolution in mobile technology," says Ryan Reith, vice president of mobile devices at IDC.

Apple has had a chequered time with developing a 5G iPhone, so here's the TL;DR version - Apple fell out with Qualcomm who used to supply iPhone modems. The pair ended up in a long legal dispute.

So it turned to Intel to supply 4G modems and worked with it on the development of a 5G modem. But Intel couldn't produce a 5G modem that was good enough (reports suggest it wasn't efficient enough and produced too much heat). So Apple decided it had to end its legal dispute with Qualcomm so it could buy its modems. It did that earlier this year, when Intel also said it would stop producing 5G modems.

Then, in a further twist, Apple bought Intel's mobile modem business. As with numerous other iPhone elements - such as the processor, graphics and more, Apple doesn't like being reliant on other vendors. So it seems set that it will use the Intel acquisition to develop its own 5G modems, just like Samsung and Huawei do.