Seoul: A major update on KakaoTalk, a mobile messenger operated by Kakao Corp., has sparked growing complaints from users, with its Instagram-like feed and increased advertisements drawing the most criticism.

According to Yonhap News Agency, last Tuesday, Kakao announced major user interface (UI) changes for KakaoTalk, its biggest overhaul in 15 years, as it seeks to evolve from a simple messaging app into a more comprehensive social media platform. The Friends tab, which previously listed contacts in alphabetical order, has been redesigned into a grid-style feed similar to Instagram, featuring photos and posts uploaded by friends, with ads of the same size placed in between.

Friends' profile update history and posts were also reorganized into a timeline format. Users, however, have voiced frustration over the changes, saying the new feed exposes too many personal updates from friends and colleagues, and unwanted ads, distracting from the app's primary role as a messenger.

"The Friends tab is filled with updates from acquaintances and even business contacts," said Lee Eun-hee, 46, who recently updated KakaoTalk. "I was embarrassed to come across my colleague's weekend schedule displayed right on the front page." She stressed that KakaoTalk is not a simple social media platform for close communication like Instagram in Korea, saying, "It's a messenger that nearly all Koreans use even in workplaces for business arrangements and information sharing."

"I disabled automatic updates on KakaoTalk after several friends advised me to," said Kim Ju-yeon, 43, who uses KakaoTalk in the workplace every day. "What people want from KakaoTalk is simply effective messaging functions."

According to pxd, a Seoul-based IT service firm, about 42 percent of 1,000 app store reviews expressed dissatisfaction with the latest version. Some 19 percent cited the UI and design as a reason for their dismay, while 10 percent pointed to problems with the Friends list and profile section. With the backlash intensifying, Kakao's shares have been hit hard. The stock fell 4.67 percent on Tuesday, when the update was unveiled, and sank another 6.17 percent on Friday.

In response to criticism that teenagers could be exposed to inappropriate content on the Short-form tab, Kakao said Saturday it has introduced additional safeguards for underage users. The company also pushed out a minor update to adjust the UI based on early feedback. Industry insiders expect Kakao to announce further improvements to the new grid-style Friends tab later this week.

"We are reviewing user responses and discussing possible changes," a Kakao official said. "Updated plans for the Friends tab could be shared soon."