ADVA Optical Networking (OTCMKTS:ADVOF – Get Rating) was upgraded by Zacks Investment Research from a “sell” rating to a “hold” rating in a report issued on Tuesday, Zacks.com reports. According to Zacks, “ADVA Optical Networking SE develops, manufactures and sells optical and Ethernetbased networking solutions. It serves telecommunications service providers, private companies, universities and government […]