Issues resolved in 7.3.8
The Atlassian JIRA team is pleased to announce the release of JIRA Software 7.3.8, which is a bug-fix release.
Don't have JIRA Software 7.3 yet?
Check out the new features and other highlights in the JIRA Software 7.3 release notes.
Released on 19 June 2017
Performance issues
We’ve noticed that this version has performance issues and shows errors while opening pages or finishing some actions. This applies only if you’re using postgreSQL and have more than 500k users. To work around it, increase the heap size by 1GB per million users. We’ll release a fix for this in the next bugfix release.
Features
In this release, we've included the Atlassian Notifications add-on, which provides targeted notifications, primarily to JIRA administrators, regarding new releases and upcoming maintenance renewals.
If you're a JIRA administrator and don't want to receive such notifications, you can go to 
> Add-ons > Manage add-ons, search for Atlassian Notifications among the system add-ons, and disable it. For more info, see Disabling and enabling add-ons.
Fixes