What's in Joomla 3.4.2?
The 3.4 release introduces new features into the CMS such as improved front end module editing, decoupling of weblinks, composer integration, Google new reCaptcha and security improvements by implementing UploadShield code which can detect most malicious uploads by examining their filenames and file contents.
UPDATE: the Install from Web Service is back online.
Thanks to the hard work of over 460 different volunteer contributors, over 260 bugs have also been resolved with the 3.4 release of the Joomla! CMS. See the list of fixed GitHub issues for details of the tracker items fixed.
For known issues with the 3.4.2 release, see the Version 3.4.2 FAQ in the documentation site.See more detail and download Joomla! 3.4.2 here