In its final written decision on October 15, 2015, the Patent Trial and Appeal Board (PTAB) found that the United States Postal Service (USPS) had proven that a patent held by Return Mail Inc. (RMI), which covers a method of handling return mail items, is invalid for claiming only abstract ideas under the Supreme Court's Alice decision. RMI sued the USPS in 2011 alleging unlicensed use of the patent when it incorporated the return mail technology into its own system. In April 2014, the USPS petitioned the PTAB for inter partes review, requesting a covered business method patent review of six of the claims.