NiziU has scored a platinum certification in Japan for their second EP 'Good Girl But Not for You,' released in April. The album exceeded 250,000 cumulative shipments, landing it on the Recording Industry Association of Japan's platinum list. The title track, 'Too Bad,' established itself as a bold, forward-thinking anthem that resonated with listeners across the region.

The platinum achievement marks another milestone for the group as they prepare for their Korean comeback. NiziU will release their first domestic mini-album, 'Sour Grapes,' at 6 p.m. on September 28. This is their first Korean album release in approximately one year and six months, following their second single 'LOVE LINE' in March 2025.

JYP Entertainment has already begun a full-scale promotion campaign, rolling out a prologue film, mood posters, a promotion scheduler, and digital artwork showcasing grape clusters and star designs across the group's official social media channels. The agency has positioned the release to align with the autumn season, signaling a shift in the group's visual and sonic direction.

Fans have expressed strong anticipation for the new material, curious to see how NiziU will balance their signature bright and approachable energy against any new artistic direction. The timing of the Korean release follows their Japanese success, suggesting the group intends to maintain momentum across both markets heading into the final quarter of 2026.