If you were a mini filer, you are not required to file a final C-4 report.
Full filers will need to file a post-general C4 (and C-3s if necessary) by December 10 and a final C-4 by January 10 if there are no outstanding debts, loans or other obligations and the surplus funds (https://www.pdc.wa.gov/learn/spending-surplus-campaign-funds) have been disposed of. If the campaign still has obligations or debts and cannot file a final report on January 10, it should continue to file on the 10th of the month (covers previous calendar month or period since last report) whenever expenditures made total $200 or more since the last C-4 report was filed. If there is a campaign surplus, but no new expenditures, no C-4 reports are required until campaign financial activity resumes.
Enjoy the quiet time before the next campaign season!