Nintendo announced on a statement, that users won't be able to add points to their Wii Shop accounts after March 26th, 2018, and won't be able to purchase on the channel beyond January 31st, 2019. Nintendo will close all services related to the Wii Shop Channel, including re-downloading purchased WiiWare, Virtual Console titles, and Wii Channel, as well as Wii System Transfer Tool, which transfers data from Wii to the Wii U system.
So long, Wii Shop Channel, your catchy song will remain in our hearts forever: