The official website of Steins;Gate released a new preview announcing the premiere of Steins;Gate Zero on April 2018. White Fox will be returning to animate the TV anime series.
MAL describes the show as:
An alternate ending to Steins;Gate that leads with the eccentric mad scientist Okabe, struggling to recover from a failed attempt at rescuing Kurisu. He decides to give up and abandons his lively scientist alter ego, in pursuit to forget the past. When all seems to be normal, he is seemingly pulled back into the past by meeting an acquaintance of Kurisu, who tells him that they have begun testing a device that stores the memory of a human and creates a simulation of them with their characteristics and personalities. Okabe begins testing and finds out that the simulation of Kurisu has brought back anguish and some new unexpected tragedies…
Source: Moca News