回複：急問，在線等：父母B2延期I－539郵寄地址

See the follwoing website for the latest information. USCIS changes this kind of things all the time.

 

http://www.uscis.gov/portal/site/uscis/menuitem.5af9bb95919f35e66f614176543f6d1a/?vgnextoid=7200ecb23683a210VgnVCM100000082ca60aRCRD&vgnextchannel=fe529c7755cb9010VgnVCM10000045f3d6a1RCRD