KLab announced that Love Live: School Idol Festival will end service on March 31, 2023. After that date, players will no longer be able to download or play the game. As of January 31, 2023, you are also unable to purchase any more paid content such as Love Gems, packs, or Passes.
While some games offer refunds on paid content that you still own at the end of a game’s life, KLab has not made any note about that on its announcement page for School Idol Festival. There is an e-mail for concerned players to reach out to. Since all Love Gems and tickets are valid until the game actually ends in late March 2023, you are likely meant to use them all up before then.
Love Live: School Idol Festival is a free-to-play rhythm game based on the Love Live franchise. It originally came out in 2013 in Japan, which means that the game lasted around ten years. There was an arcade version available as well, though it shut down in 2021. School Idol Festival often ran collaboration events with other intellectual works. For example, it had a Persona crossover and a Code Geass one in the past.
Love Live: School Idol Festival is readily available for mobile devices, and it will end service on March 31, 2023. Players will have until that date to download the game and use up any remaining premium items.