You can bypass the need for the update if you turn off your internet before opening the program.
Generally speaking, program updates should not change your as-filed return. Sometimes, certain tax forms and items are delayed and are not ready until February or March, but if you are affected by one of those situations, the program should not let you file until the IRS has approved the forms. Whatever tax situations are included on your return, Turbotax and the IRS will not allow filing until the IRS has indicated final approval for the forms and instructions that cover those situations. So any changes that happen in the program after you file should not affect your as-filed tax return.
If a program change does affect your file, that probably means you need to file an amended return. But Turbotax should know who is affected by late changes, and be able to email affected customers directly.
To avoid creating changes to your as-filed tax return, save a copy of your data file in a safe place, and do your experimenting on a copy.
