It was announced on Kiniro Mosaic
's official Twitter that a sequel has been confirmed. The type of the anime (TV, OVA, or movie) has not yet been stated.
Source: Kiniro Mosaic anime tweet
News submitted by game8910
Update April 17
According to the upcoming issue of Manga Time Kirara Max magazine, the sequel will be a TV second season.
Source: Scan via ANN
Kiniro Mosaic 2nd Season