SAN FRANCISCO >> Apple is expected to unveil its biggest and most expensive iPhone on Wednesday as part of a lineup of three new models aimed at widening the product’s appeal amid slowing sales growth.

If media leaks pan out, the newest additions to the iPhone lineup will make their debut at a scheduled company event in California.

Most of the buzz is swirling around a rumored iPhone that is supposed to boast a 6.5-inch OLED screen, up from 5.8 inches on the existing iPhone X. OLED is a step up from traditional LCD technology in offering a display without a backlight, so black is truly black rather than simply dark.

The iPhone X became the first mass-market smartphone to sell for $1,000, and now Apple is upping the ante again.