Kingdom Hearts Union χ[Cross] Dark Road will be coming to a close on May 30th. The app will switch over to offline mode at May 30, 2021 at 6:00 p.m. (PDT) / May 31, 2021 1:00 (UTC). After this date, the Union χ[Cross] side will only be available in theater mode while Dark Road won't be available until Version 5.0.0 rolls out in late September.
In addition, The story of Union χ[Cross] will conclude in April. You can read more information by clicking here.
Kingdom Hearts Director Tetsuya Nomura has provided a statement regarding the ending of χ[Cross] Dark Road. You can read it below.