A divergent continuation of the original Steins;Gate ending, Steins;Gate 0 explores an alternate worldline where Okabe abandons time travel.
Additionally, the 2013 film Steins;Gate the Movie will be returning to Japanese theaters with a limited run at the Cinema Sunshine Ikebukuro venue beginning on July 20, 2018.
The postcards are available while supplies last, and are limited to one postcard per purchase per person.