Joomla! 3.9.10 Bug Fix Release announced
Joomla! 3.9.10 is a Bug Fix Release.
It addresses a bug introduced with Joomla! 3.9.9.
The Joomla! Project advise all Joomlers to NOT implement the Joomla! 3.9.9 Security Release BUT instead implement Joomla! 3.9.10.
Joomla! 3.9.10 also addresses the security vulnerability addressed by Joomla! 3.9.9 but does not include the bug!
If you have already implemented 3.9.9 AND you administer a multi-lingual website then you are advised (by the Joomla! Project) to read the Joomla! 3.9.10 Release Notes before updating your website.
More details at the following link.
Back up before updating is highly recommended
When you read the Joomla! 3.9.10 Release Notes you will understand why it is essential that you back up your website before implementing a Joomla! CMS update.
Or for that matter any Joomla! extension.
Protect your assets!
Perform a FULL backup of your website (database and files) BEFORE updating the Joomla! CMS and/or its extensions.