Ditama said in his fan book that this kissxsis project was originally planned to be released in c101 but due to quality issues of the art and his actual job betting in the way it was postponed. If you read in his fanbox post on 20Jan23, you'd see in his 48 page doujin, 20 pages were still in very rough sketches and on 23Jan23 he posted that he's targeting to release the digital version in mid-Feb and the printed version in March.