The iPhone has been struggling, and it doesn't sound like this year's launch will be what Apple needs to save it

Analysts at Credit Suisse also described this year's iPhone launch as "incremental."

"We're encouraged as Apple continues to recover from a difficult start to the fiscal year; however, iPhone remains a sustained drag heading into what we view as a more incremental fall launch cycle," read the note, which was authored by Credit Suisse's Matthew Cabral, Dan Knauff, and Michael Allen.

In a note authored by Canaccord Genuity's T. Michael Walkey and Anthony Nemoto, the firm said it expects to see iPhone unit growth in 2020. It mentions the 5G iPhone in the context of driving higher iPhone sales.

"Given the continued near-term soft sales trends for the latest lineup of iPhones, we forecast a 12% year-over-year unit decline in C'19 iPhone sales and anticipate 10% unit growth in C'20 based on an increasing installed base driving higher iPhone sales including those from the anticipated introduction of the 5G iPhone next fall," the note read.

Raymond James believes the 2020 iPhone could return iPhone units to growth, the firm said in a note written by Chris Caso and Melissa Fairbanks.

"We continue to expect a weak iPhone cycle through June '20, and while expectations are already low, we don't see a catalyst until the Fall '20 5G iPhones," the note said. "But our upgrade earlier this month reflects our conviction that cycle (which we expect to include wide availability of 5G throughout the iPhone lineup) will return iPhone units to growth and repair the mix deterioration within the iPhone lineup. While that catalyst remains more than a year away, we have chosen to be early in our call."

A team of analysts at Morgan Stanley led by Katy Huberty views the reported 2020 5G iPhone as the impetus that could return iPhone sales to growth.

"We see the potential for meaningful multiple expansion as new Services re-accelerate growth and Apple approaches the September 2020 launch of 5G iPhones, which have the potential to accelerate upgrades and return iPhone to meaningful Y/Y growth," the note read.