XPS chief Frank Azor has been fielding some questions on Twitter in regard to the Dell XPS 15 and its expected OLED panel update. The executive effusively responded "yes" to one question about whether it was coming but had less positive answers for other inquiries. Unfortunately, there is still no fixed timeframe for the OLED option.
https://www.notebookcheck.net/Dell-XPS-15-No-OLED-panel-option-for-the-2-in-1-but-still-coming-for-the-main-series-no-white-SKU-planned.418981.0.html