STOP Act 2.0 This bill revises requirements related to advance electronic data (AED) on international mail shipments. (The STOP Act of 2018 requires international mail shipments coming into the United States to have AED to address the threat of synthetic opioids and other dangerous items.) Specifically, the bill establishes a new criminal penalty for knowingly misrepresenting the country of origin of an international mail shipment in order to avoid AED requirements. Additionally, five years after enactment, the bill terminates U.S. Customs and Border Protection's authority to exclude countries from AED requirements. The bill establishes additional reporting requirements related to AED, including a requirement for the Department of Homeland Security (DHS) to report the results of randomized tests of packages entering the United States. Further, the bill authorizes DHS, the Department of Justice, and the U.S. Postal Service to enter into partnerships with private parcel services or other private information technology entities to develop technology and processes for identifying the origin of fentanyl, other synthetic opioids, and other narcotics and psychoactive substances. The bill also authorizes DHS to share with and receive information from foreign governments regarding (1) shippers with a history of transporting illegal substances, and (2) best practices for detecting the substances. U.S. Customs and Border Protection must train its officers in detecting illicit fentanyl and other synthetic opioids. Finally, the bill directs the Government Accountability Office to evaluate the implementation of the STOP Act of 2018.