For all of our Joomla Hostingcustomers out there:
Joomla has released version 1.7.2. Those of you using a previous version (1.6.0 to 1.7.1) should update your Joomla installation as soon as possible. For more information, please visit Joomla’s release page.
If you are running a 1.5 version Joomla website, there is an update available for you as well which you can read more about here. You should update as soon as possible. You can download Joomla 1.5.24 upgrade patches from here.