USPS updated their API this week and Marketpress hasn't been updated since July, so it appears it has not been updated for the API changes. My First-Class Parcel products that are under 4oz are no longer being tagged with correct postage. A 0.96oz product cannot fit in a bubble mailer (we don't have bubble mailers setup as an option) and shipping is getting priced at $0.49 - $0.70, where it should be closer to $2.00 (usually around $1.93).
I see that other eCommerce solutions have released updates for the September API updates. Please help ASAP! We have had to disable First-Class Parcel as an option and this could cost us business.