An employee, left, shows a customer the features of an iPhone 11 at Apple store during a product launch event in Kuala Lumpur, Malaysia on Friday, September 27, 2019.

Apple is gearing up for its next iPhone launch this fall, but plans could shift as the company delays production, according to a new report.

The Wall Street Journal reported Monday that mass production for new iPhones has been pushed back "about a month." That means that even if Apple announces them in September, as it usually does, some or all of the models might not be available to buy in September.

The report says Apple is planning four new iPhones, including one with a 5.4-inch screen, two with 6.1-inch screens and a big model with a 6.7-inch screen. It's unclear how many of those phones may be impacted by the delay — the report just says "flagship iPhones" — but some analysts have said Apple could push the launch of some or all of its new phones.

Before the coronavirus pandemic hit, many analysts expected Apple's next iPhone models to kick off a "super cycle" of upgrades thanks to an expected redesign of the phone and the addition of 5G. A significant portion of the iPhone installation base is still made up of models that launched as long ago as 2015, and the hope was the 2020 iPhone models would have enough new features to encourage those users to finally spring for an upgrade.

In January, Susquehanna said Apple's decision to create its own antenna package modules would delay its fastest 5G iPhone into December or January. Bank of America said in March the 5G iPhone could be delayed due to the coronavirus. JPMorgan said Apple's new iPhone could be delayed one to two months. And Nikkei Asian Review said in March that Apple was considering delaying its iPhone launch by "months" because of issues related to consumer demand during and after the Covid-19 epidemic.

Top Apple analyst TF International Securities analyst Ming-Chi Kuo said he expects the coronavirus to negatively impact iPhone shipments by 10% to 15%. It's not just production issues either. With so many jobs lost due to the pandemic, it could be hard for Apple to persuade people to upgrade to its newest phones, which can cost $1,000 or more. Last week, Apple launched the iPhone SE, a cheaper model that starts at $399. It has the same processor as the top-tier iPhone 11 and an improved camera but utilizes the same design with a home button that Apple has offered since 2014.

Kuo said earlier this month that he believes Apple's 6.1-inch and 5.4-inch iPhones will enter mass production in September and that a larger 6.7-inch model wouldn't be mass produced until October "because this model's design is the most complicated."

Apple has done this before. The iPhone X was announced at the same time as the iPhone 8 and iPhone 8 Plus, in September 2017, but the top model didn't ship for two months.

Apple was not immediately available to comment.

Read more from The Wall Street Journal.