WordPress MU 1.3.2 has been released and is a critical update including a “security update that brings together the fixes in WordPress 2.3.2 and a number of critical WordPress MU specific security problems”.
This release should be seen as an urgent upgrade.
Donncha states in his blog post that the “details of the fixes will be posted to the WordPress MU forum next week to give administrators time to upgrade”.
Before upgrading, check this post in the MU Forum if you are using any plugins in your current installation that uses options.php to save it’s options. You must now whitelist those options using the new add_option_update_handler() API.
(read this forum post for the best instructions on how to upgrade your WordPress MU installation.)
