Incident: Delta B767 near Boston on Jun 22nd 2017, problem with minimum/maximum speed indications

A Delta Airlines Boeing 767-400, registration N834MH performing flight DL-174 from Atlanta,GA (USA) to Milan Malpensa (Italy), was enroute at FL330 about 190nm southwest of Boston,MA, almost over New York City, when the crew descended the aircraft to FL250 and then FL230 due to problems with the maximum and minimum operating speed indications (avherald.com) Plus d'info...