Supplement J FAQs

My I-485 was pending for 9 months (concurrent filing), and I worked all these years (4 years) with my sponsoring employer. My I-140 was approved 4 months ago, and I received EAD and AP as well. At the end of 8 months, I resigned from my employer to take advantage of AC21 (moving to a similar position) and was on notice period. My new employer was ready to file I-485J when asked by USCIS. During my last working week with my sponsoring employer, my 485 got approved, and I received my GC. Can you please advise on what kind of documentation I need to get from my new employer to help with any future naturalization process since I can't file I-485J as my case has been approved?