Olympus Tax is 100% correct.  This has NOTHING to with either IRS or ProSeries not having the form finialized.  Nor does it have anything to do with 3/17 or some later date.

If I transfer the client from 2020 to 2021 and an amount does not come forward, what will happen when the program does get updated?  How will the amount magically appear in a return that has already been transferred and worked on?  If it will, great.  But if it won't, is the answer to not do the transfer, and not do any work on these clients, until such point that the form is finalized so something will transfer?

I have been doing this long enough to know I NEVER mess with carryover amounts as there are so many things going on in the background so to me, working on a client and just "dropping" in a carryover amount later is not an option.  Might work for you, not me.

It would be nice if there was some info on how specifically this will work.