Chessdom has posted an update. Season 13 is due to start on Friday 3.8.18, the undisclosed NN engine is called DeusX and the hardware will indeed include a CPU machine for traditional engines and a GPU machine for the NN engines. There are still 3 engines in division 4 whose identity has not been published yet.
I am still on vacation, and will probably miss division 4
Orignal post - 26.7.18:
The TCEC website is currently unavailable as Season 13 is being prepared in the background. There has been no official press release on chessdom or on facebook yet. According to the chat we are expecting new GPU hardware for this season, and at least two neural network based engines using it - Leela and an undisclosed mystery engine.
The site administrator for TCEC has changed again. The previous administrator KnightMoves left quite suddently, I did not witness the event and I don't know what happened exactly. As a result the new GUI that was developed during the past few months is gone as well. The new administrator will have to get acquainted with the system quickly, including the new hardware. I wish him good luck and I hope that TCEC will run smoothly.
I am on vacation for a few weeks and will miss the start of the season, if indeed it starts soon as planned. I hope to start posting again when I get back in the second half of August.