What clothing should one wear to the reception?

Can anyone who attended some of the earlier receptions write what sort of clothing the other kids were wearing? Formal? Non-Formal?

Did you read other posts related to the reception? they said everyone dressed in a casual attire.

We attended the San Jose reception yesterday. My son wore jeans, a button down shirt and a very casual jacket. I wore business casual (slacks, cardigan). Most young men and many fathers wore jeans. Definitely not formal!