Expiry date of (Wilton) Royal Icing Mix? Plus, how do I make my own without (dried) egg whites/meringue powder?

Hi! I have a box of the Wilton Royal Icing Mix that I've never had a reason to use.. until now. The thing is, I have no idea whether I bought it 1 year ago, or two. I stored it in a dry place and it is completely sealed. It's almost all sugar but I'm worried about the dried egg whites in there.

Would you still use it? How do I find out if it's still good, the only thing on the box is the serial number (13064).

I don't live in the U.S. so I can't just call, it's Easter anyway.

The other question is, how could I make my own icing that is similar in its properties (smooth, forgiving) but does not include egg whites? Where I live, there are no pasteurized egg whites, no meringue powder and no egg white powder. The only option I'd have are raw egg whites and I don't want to give people stuff with raw egg whites. Predicciones del brujo mayor.

Any ideas?