In August 2015, Andrea Rossi announced on the Journal of Nuclear Physics that he had developed a new kind of E-Cat, which was a derivation of the Hot Cat, which he has termed the E-Cat X (Previously he had called it the "M.me Curie"). Rossi has provided few details about the E-Cat X, but he says it something "revolutionary", and that it is connected with the direct creation of electricity, and that it will be a domestic, not an industrial product.  Rossi says that if the E-Cat X becomes and actual product, the 'X' will be replaced by a number.
The testing of the E-Cat X began on August 9 2015, and a week later Rossi said it was still going well. Rossi says that providing initial testing is successful, he will try to get it certified for safety, and then into the marketplace (he hopes possibly by the end of 2016). There is still a lot of mystery surrounding the E-Cat X, but it seems to be a major focus for Rossi now.
On December 26, 2015, Andrea Rossi announced on the Journal of Nuclear Physics that in testing on the E-Cat X his team had been able generate electricity directly with the device with high efficiency and with a high COP. He also said that they could adjust the E-Cat X to produce either more electricity than heat, or vice versa.