Little white boxes hooked up to WiiConnect24 in the US should have a little blue light emanating from the front as Nintendo have updated the Wii's System Menu yet again.
According to the letter delivered by Nintendo's digital pigeons:
This update provides behind-the-scenes fixes that will not affect features but will improve overall system performance.
Poking about the System Menu after the update, it would appear that the pigeon was spot-on in its assessment that features are unaffected. As for the overall performance boost, well, we'll just have to take your word for it, Nintendo.