Joomla version 3.6.3 came out last week and it had bug fixes but the 3.6.4 version is a security release and we do suggest everyone do this upgrade immediately.
Joomla! 3.6.4 Released (joomla.org)
Joomla! 3.6.4 is now available. This is a security release for the 3.x series of Joomla! which addresses two critical security vulnerabilities and a bug fix for two-factor authentication. We strongly recommend that you update your sites immediately.
This release only contains the security fixes and bug fix; no other changes have been made compared to the Joomla! 3.6.3 release.
TYPE OF UPGRADE: Security
MAJOR OR MINOR: Minor
SUGGESTED ACTION: Get it done now.
WHY: To fix security issues in the software.
Our Website Maintenance Department will be in contact with all of our clients running Joomla regarding these upgrades and we'll get you a quote.