The latest release comes with the most of the Joomla Core library changes that will be included with Joomla version 4.0.0.
It is recommended to check the alpha version and use the new features only on the demo sites. Developers can test their extensions and report their suggestions.
What is the difference between Alpha 9 and Alpha 8?
The latest update brings bug fixes from the previous version. The introduced fixes and improvements will be included in the Joomla 4.0 release.
Take a look at the list of the most important features expected in Joomla 4: