Nintendo pushed out a Wii Shop Channel update this evening. I just got the Wii-mail a few minutes ago, so this almost qualifies as actual news!
The only official reason seems to be that users who paid 500 points for the Wii Internet Channel, which was free early on and was recently made free again, can now download one free NES game, an equivalent value. Not a deal, per se, but a nice thing to do nonetheless.
The Wii firmware remains at the same version, 4.2U.