With reports dating yesterday, the Taiko no Tatsujin Tokumori! (Wii U2) main site has recently added the notice that the digital/download version of the game will be deshelved from the Nintendo eShop after October 31 2019 at 12:00 JPT.
Those who already purchased the game through digital means can still play already-downloaded copies, or re-download if the game was removed from the console.
Check the full original notice via the "Notice of Termination of Download Version" (ダウンロード版配信終了のお知らせ) button.
