Resolves YES if by 7/1/2023, NHC reclassifies Hurricane Ian as Category 5 based on reanalysis. Otherwise NO.

(If Hurricane Ian simply strengthens to Category 5 again somewhere in the Atlantic, that does not count for this question. What does count YES is if NHC decides that Hurricane Ian was actually Cat 5 at some point where it had previously been classified Cat 4.)

From excellent comments by @marthinwurer on https://manifold.markets/jack/will-hurricane-ian-strengthen-to-ca-d11322584389:

the NHC will occasionally issue upgrades later in the season, based on data from reanalysis. They did that with hurricane Michael, which intensified to a cat 5 right before it hit. Ian was just two mph under the cat 5 line and showed a lot of signs of intensification towards the end, so it might be upgraded after the fact as well.

it appears that they publish the reanalysis studies the following spring.

I don't think they'll increase the operational classification until then, as there's more important forecasting to do because it might landfall again on the east coast once it crosses Florida and emerges back into the Atlantic.

For reference, Michael was reclassified as cat 5 on 4/19: https://www.washingtonpost.com/weather/2019/04/19/hurricane-center-upgrades-michael-category-first-since-andrew/