父母沈阳签证DS-156/157 是否一定要网上在线填写并有条形码？

父母沈阳签证B2，请问是否一定要网上在线填写并有条形码? 沈阳驻美使馆网站并没有明文要求。 现在北京使馆是要有条形码的。多谢帮助！

My parents are going to apply B2 at Shengyang. I am not sure if they have to fill out DS-156 online in order to generate Bar Code for form submission purpose.

Anyone knows the answer?

Thanks a lot!