Will the data from my upgrade rollover to the next month if it is not used?

Yes it will roll over with an expiration of 60 days after that it expires

It will rollover for two renewal cycles. After that, it's gone

There is a graph with the expiry dates of your mobile data on your Fizz account.

Oh my bad, Elizabeth was asking about upgrade rollovers, which is the same as regular plan data rollover (2 cycles).

For some reason, I was thinking rollover for gifted data (which is 1 cycle).

One way to think of it is: allocated data has a 90 day validity (whether from an upgrade, or you monthly allocation).

Yes it will

Yes, it now rolls over. It's great to know that you have lots of extra data when you need it.