According to the publication The Bell, Apple can continue to produce smartphones with LCD displays and in 2019.
This decision is due to several factors. First, because of the complexity of the production of OLED displays for iPhone X in 2017, Apple had to face a shortage of components. Second, sales of the iPhone 8 and iPhone 8 Plus the usual LCD displays was very high.
It is unlikely Apple will be ignoring the needs of the market. Therefore, ambitious plans for a large scale OLED screens are likely not to be fully utilized.
Production of LCDs is cheaper and easier. This affects the final price of the product. As shown by the sale, not all consumers are willing to pay several hundred dollars for innovative OLED screen.
So versions of the iPhone, equipped with liquid-crystal panels will remain in the lineup of Apple smartphones, at least until 2020.