Miiverse will be undergoing some major maintenance next week, during which the service will be down. While Miiverse is down, game functions that use Miiverse will not be available either. Nintendo gives the specific examples of BLADE functions in Xenoblade X, uploading courses or showing comments in Super Mario Maker, and uploading screenshots, stages, and replays in Super Smash Bros. for 3DS and Wii U. The estimated maintenance times are listed below:
North America (EST): June 6th, 10PM to June 7th, 6AM
North America (PST): June 6th, 7PM to June 7th, 3AM
Europe: June 7th, 4AM to 12PM
UK: June 7th, 3AM to 11AM
Japan: June 7th, 11AM to 7PM