Joomla 3 is the latest major version of the Joomla CMS, with 3.9 being the tenth minor release in this series.
Please note that going from 3.8 to 3.9 is a one-click upgrade and is NOT a migration. The same is true for any subsequent versions in the 3 series of the CMS. That being said, please do not upgrade any of your production sites to the alpha version as this alpha is ONLY intended for testing and there is no upgrade path from Alpha.
What’s new in Joomla 3.9?
Joomla 3.9 main purpose is to introduce a Privacy Tool Suite into Joomla CMS to facilitate the compliance of your sites and to make developers’ life easier to get their extensions compliant with laws and regulations such as GDPR.More information