The usually reliable Apple analyst Ming-Chi Kuo expects Apple to launch its first 5G iPhone in 2020. He also expects we will see a new smaller 5.4-inch model along with a larger 6.7-inch device both with 5G connectivity. The iPhone XR-style model will get OLED for the first time, but will continue with the 6.1-inch form factor.
https://www.notebookcheck.net/Ming-Chi-Kuo-2020-iPhones-will-go-all-OLED-include-5-4-inch-and-6-7-inch-5G-models.424639.0.html