Joomla! 3.4.8 is now available. This is a bug fix release for the 3.x series of Joomla This release fixes some bugs related to session management from Joomla 3.4.7. The project understands that many of our users are now on Christmas Holiday's so we would like to emphasise that this release only contains bug fixes and whilst we strongly encourage our users to update as soon as practically possible, this update can be left until after any holidays.
What's in 3.4.8

Joomla 3.4.8 fixes some issues found in the 3.4.7 release on Monday to do with browser sessions. All reported bugs from the 3.4.7 update have been fixed in this release:

• Users were unable to edit or create items after the 3.4.7 update
• Fatal error about connection->stat() not existing on external database connections
• After session timeout users could still navigate the backend but without being able to create/edit items or use pagination/filters

You can read full release note here: https://www.joomla.org/announcements/release-news/5644-joomla-3-4-8-released.html