On July 27, 2015, several questions were brought up to VOCALOID EMPIRE's twitter account. It was confirmed that UNI would have more than one voicebank and it was hinted that she may be able to sing in multiple languages. However, the certainty of these claims was later thrown into question by a translator. Korean tweets suggested UNI would only be released with one voicebank, but more if she was successful.
On June 17, 2016, a sample of UNI's voicebank was released. It was revealed that she would be capable of cross-synthesis and was set for release in September. An English voicebank was slated for 2017. It was also mentioned that her voice provider had changed during production. At this point in time, the demo utilized a "Soft version" and was still in development.
On November 16, it was later announced that UNI's Korean voicebank was delayed to January 2017. However, her "Append" voicebanks, Power and Soft, would be released separate from the original voicebank in Summer 2017.