How to fill question 11b on I-539 form

Do I write the passport number mentioned on my i94 or my new passport number . My old passport has since expired but since I haven’t left the country post the issue of my new passport, my online i94 shows my old passport number. Please advise

You should enter the passport number that is currently valid and used by you. You should always enter the details of the current passport. You can submit copy of your old passport and new passport. The new passport has the old passport number as a reference in back pages.