File an extension

On a complex estate it is practically necessary to fill in the 706 as information is obtained.  This lets the preparer consider alternative and elections as well as plan for funding the tax liability.  It is worth more than I pay for this software to be able to enter the information this way.  The liability on a 706 can be in hundreds or thousands or millions of dollars.

A 706 is not like a 1040.  Extensions are only used if absolutely necessary in order to obtain all information to file the return.

I understand that. You can work in the 2020 program and then redo it when the 2021 is released.

You can file an extension and prepare the 706 when the 2021 program is released.

You can get the 2021 forms from irs.gov and fill them in manually.

You can override the credit in Screen 28. I'm not sure what else this might mess up.

The 706 form isn't released annually; the last update was August 2019.  If the program is only updated annually, it's useless for decedents with a date of death in the first few months of the year.  But why can't you just insert the correct amount on Line 9e?  If Lacerte put something there, just replace or override it.