I’m so glad my post was of help to you! I totally understand what you’re asking, and I agree with the other commenters, it really depends on whether you were required to file based on your worldwide income, not whether it was U.S. income.
In my case, I didn’t file because I didn’t have to (under the filing threshold), and that’s why it went smoothly. I brought the IRS Verification of Nonfiling Letter, and I also included a simple signed/dated explanation letter/affidavit. No notarization.
If you did meet the filing requirement for any of those years, then I’d recommend getting your taxes filed and fully up to date and having everything ready before submitting the I-864 / going through DCF, it’ll save you headaches later for sure.
Hope that helps, and wishing you a smooth DCF process!
