We release Tarski updates fairly often—usually about once a month. You can get new versions either by downloading them as a .zip file, or from our Subversion repository. Future releases are tracked on the roadmap.
Backing up
Tarski is designed to let you modify your site without changing core theme files. However, before you upgrade Tarski, it’s important to back up any custom styles, custom sidebar file, and if you’re still using one, your constants file. If you’ve modified any theme files, or added your own templates, you should back those up too. Other changes should be saved in the database, or made via plugins, neither of which should be affected by upgrading Tarski.
Updating
Once you’ve backed up the files listed above, delete everything in the Tarski directory. Download the latest version and extract the contents into your Tarski directory, before adding any personalised files back where they should be. Check your site to make sure everything is working properly; any problems with the upgrade should be posted on the forum.
The update notifier
Tarski comes with an update notifier that lets you know when new versions are available. It can require a little configuration, so please check the update notifier documentation page for instructions.