Shut down of Online Services for Nintendo 3DS and Wii U

What will happen and what it will entail

Nintendo on Nintendo support offically announed that, on 4 PM PDT, April 8, 2024, the Wii U and 3DS will cease online play support and other related functions. This includes but is not limited to:

A Q&A is offered on the announcement, giving answers to questions like "Can I still play offline even after online services end?" or "Is it still possible to download update data or purchased software?"