WordPress MU 2.6

Version 2.6 of WordPress MU is now out! WordPress MU is the multi blog version of the popular blogging software WordPress. It’s the engine behind WordPress.com and many other blogging sites.

This version of WordPress MU is based on WordPress 2.6. There’s a long and interesting WordPress.org post on the new features in 2.6 so get over there to read up on post revisions, “Press This!”, Gears, Theme Previews, and the long list of developers who helped make this release a reality.

Some of the new features in this release of MU:

1. Version number is 2.6 rather than 1.6 because it just makes sense to synchronise the major version numbers.
2. Signup page now has a nonce which should help in the fight against spammers, for a short while anyway.
3. Redirecting to the signup page for 404s and for unknown blogs is not enabled by default. Check out wp-config-sample.php for instructions.
4. “allowed_themes” filter, much like the plugins filtered added previously.
5. New functions: get_id_from_blogname(), is_main_blog().
6. get_blog_details() can now take a blogname as well as a blog_id.
7. Custom first posts didn’t always work. Now they do.
8. Blognames in the “Add blog” form in wpmu-blogs.php are now sanitized.
9. Added “pre_site_option_*” and “site_option_*” filters like the similar option filters.
10. Meta fields will be passed on signup again.
11. Added an “admin_header_navigation” filter so the top right navigation in the backend can be customised.
12. The signup page uses “blogname” instead of “blog_id” to avoid confusion with the global variable of the same name. Plugins will break if not updated!

That last change is quite a major one. If you have any plugins that interact with the signup form they will need to be updated!

This release also addresses some security issues spotted by Alexander Concha and Juan Galiana. Thank you both for alerting us and for your patience while this release was prepared!