By 
Gundam Breaker Mobile service will end on June 5, 2023. This was a smartphone game more focused on the Gunpla aspect of the franchise. You will no longer be able to purchase items in the shop from May 8, 2023. [Thanks, Famitsu!]
There is not a lot of information on the official webpage for Gundam Breaker Mobile in regards to why it will shut down. It thanks all of the players that have supported and played the game since its debut before revealing the roadmap until its closure. While the shop will close on May 8, you will still be able to use any Haro Chips that you’ve previously purchased until the game officially shuts down.
Gundam Breaker is a PS3 and PS Vita game that focuses on Gunpla rather than the mobile suits that you see on the shows. You can defeat other units and essentially cannibalize their parts to create your own unique mobile suit. This is the mobage version of that game, with basically the same features and gameplay.
Gundam Breaker Mobile will no longer be playable from June 5, 2023. Until then, it is available on mobile devices. The latest Gundam anime as of the time of writing, season 2 of The Witch From Mercury, will start airing from April 9, 2023.
