Service announcements
2019-03-13 15:45: Joomla! 3.9.4 security updateJoomla! 3.9.4 was announced 12 March as security update for all previous Joomla! editions.
Joomla! 3.9.3 and older versions are therefore considered to be insecure.
If you're using Joomla! 3.9.3 or older versions, you must upgrade to 3.9.4 as soon as possible.
Source: joomla.org - 3.9.4 release announcement