WordPress MU 1.2 just released not long ago, according to Donncha, most of the changes are bug fixes, but there are some security fix as well, so it’s advised that all the WordPress MU user upgrade to the latest version! And if you encounter any problems, please go to WordPress MU forum.
Apparently there are some problems with the theme in WordPress MU 1.2, but worry not! Because version 1.2.1 is here!! 😆 So if you upgrade from 1.2, all you have to do is just change the following files:
Oh and don’t forget to go
"Site Admin > Themes" and click save to update the theme list! 😉