is it ok to use powered sugar with the experiation date of 2015?

Little chance of spoilage, but it can absorb odors in storage.

FYI safety also confirmed by stilltasty.com site which uses cdc, fda & usda data.
They say it "keeps indefinitely"

Confectioners or powdered sugar is pretty shelf-stable. It's just sugar and cornstarch. I use a box over a period of years. I'd have no qualms using it past expiration date.