This update is very important as Joomla team had fixed couple of high severity security vulnerability along with more than 230 bugs.
Security Vulnerability that were fixed in this version are-
- Core - Information Disclosure (affecting Joomla 1.7.3-3.7.2)
- Core - XSS Vulnerability (affecting Joomla 1.7.3-3.7.2)
- Core - XSS Vulnerability (affecting Joomla 1.5.0-3.6.5).
Among these first two were rated high severity and third one is of low concern. All these vulnerability reside in a core Joomla CMS.
Other then the security vulnerability, there there are lots of improvement made by team, such as-
- Calendar fixes #16794
- Fix frontend menus of menu type "main" or "menu" and back end main menu #16577
- Tags: Respect Browser Page Title in view Tagged Items #16773
- Adding thumbs file names in Media Manager #16769
- Remove PHP memory_limit from max upload size calculation #16741
- Fix custom fields without a fieldgroup not being displayed #16705
- Update tinymce to 4.5.7 #16042