There are several projects taking place around the Magic Kingdom, including several "new to me" changes.
First and foremost, as we originally reported on Twitter, several fish have been re-painted with black light paint just before the Under the Sea scene in the Under the Sea: Journey of the Little Mermaid attraction. Unfortunately we were unable to take a decent photo of this change, but it adds credibility that the upcoming refurbishment will be to re-paint several parts of the attraction using black light paint, similar to what was done in Disney California Adventure.
Splash Mountain is closed for it's annual refurbishment, an exterior photo can be found below:
It appears that some of the glass in the Seven Dwarfs Mine Train cottage scene has been removed or changed to one with less glare. Previously, this scene was difficult to view during the daytime because of the glare/reflection off the glass.
Work is ongoing on the Cinderella Castle Hub project:
I never noticed this note to Sarah in the Valentine's day scene (Scene 1) of Carousel of Progress:
The Main Street USA bypass was in use this weekend, here's a look at some of the faux brick facade.