İ have come across an article about a new engine that TEI has been working on for TB3. This new engine is supposedly a diesel hybrid;
Baykar Bayraktar TB3
The latest iteration of the successful Bayraktar TB2 Tactical UCAV, the TB3 model's main difference will be in propulsion.
Tusaş Engine Industries (TEI) will be contracted to develop the TEI HE-150 hybrid diesel-electric engine, capable of producing 150 hp. Coupled with quieter propellers, the aim is producing a much quieter UAV while using electric propulsion over contested areas, reducing detection.
The new engine is expected to be lighter and output more electrical power for use by sensors. Satellite communications will be added to extend communications range to the point it is no longer the limiting factor (that would be flight characteristics instead).
Officials from Baykar have confirmed that existing Bayraktar TB2 will be able to be upgraded to TB3 standard. Development time will last three years, mainly focused on the engine. Baykar, a private company, has invested $200 million into development, expecting to win contracts for upgrade the Turkish Armed Forces' existing TB2s.
Can this be what is being mentioned in media now? This article is over a year old though.