Like vultures hovering above a corpse, Ericsson’s rivals have been hanging around waiting for former Mediaroom customers to lose faith in their migration path and then pounce with their alternative multiscreen platforms. This is a long running saga dating back to the days when Microsoft still owned the Mediaroom IPTV middleware well before its sale to Ericsson in 2013, but lately the story has taken a new turn amid speculation over its owner’s possible sale of the pay TV business. The original picture was one of Microsoft’s neglect for Mediaroom at a time when it was refocusing on OTT and its Xbox gaming platform, which was precisely why it put the middleware up for sale. Mediaroom was born out of…