I'm pleased to announce that symfony 1.4.12 has just been released. This release contains minor bug fixes and typos. The CHANGELOG has all the details about the changes.
If you've checked out a copy of the tag from Subversion you can switch to the latest version:
$ svn switch http://svn.symfony-project.com/tags/RELEASE_1_4_12
If you are using the PEAR package you can update using the pear command:
$ pear upgrade symfony/symfony-1.4.12