According to Koei Tecmo and Gust, the delay for Ciel nosurge: Requiem for a Lost Star DX and Ar nosurge: Ode to an Unborn Star DX was put in place to further improve the quality of both high resolution remasters.
Ciel nosurge and Ar nosurge were originally released on PS Vita and PS3, respectively, back in 2012 and 2014, and they’re scheduled to get a new lease on life on PS4, Switch, and PC soon.
Fans will have to wait a little longer, though, because the Japanese release has been delayed from January 28 to March 4, 2021.