If you divorce before filing Form I-751, you must file it alone with a waiver you can’t file jointly anymore.

You can file at any time after divorce, even before the 90-day window prior to your green card’s expiration.

If abuse occurred during the marriage, you may also qualify for a waiver based on battery or extreme cruelty.

If your divorce isn’t final yet, you may file jointly and update USCIS once the divorce is finalized or request extra time to submit the final decree.