回复：请教老猫:如果离婚后以前填的I864A还是否有效

根據廣州美國總領事管的網頁中的資料來看
http://guangzhou.usembassy-china.org.cn/changes_to_affidavit_of_support_requirements.html

The Department of State has recently changed its requirements for the I-864, I-864A, and I-864EZ Affidavit of Support form. Previously, State required copies of a sponsor’s federal income tax returns for the three most recent taxable years, along with evidence of current employment. Effective immediately, State only requires a certified copy of the most recent federal income tax return.
所以如果您願意提供您今年的報稅資料給您的前妻，這份資料應該仍然有效，否則這份申請自動失效。