Nintendo has confirmed that it's taking down the eShop online stores for its different platforms, including the 3DS and Wii U, as well as the Wii Shopping Channel and the DSi shop for a period of network maintenance today, April 22.
Nintendo is getting ready to roll out a special firmware update for the Wii U console, not to mention other services for the home device, as well as for the 3DS handheld.
As a result, Nintendo has just confirmed on its support page that a period of extended maintenance would take place today, April 22, between 1pm PST and 7pm PST.
During this time, the eShop for the Wii U and 3DS consoles will be unavailable, as will the Wii Shopping Channel and the DSi Shop.
You can expect to hear more about the outage soon.