During the upgrade, the new "Administer Security Hotspots" permission is granted to all users/groups who already have the "Administer Issues" permission.
Starting with this version, Compute Engine logs will be more verbose. These logs are rotated automatically, but on a daily basis, not based on file size.
SonarQube 7.3+ only supports PostgreSQL 9.3 to 10. SonarQube will not start if you are using a lower version of PostgreSQL.
APIs deprecated before SonarQube 5.6 are dropped in this version, making some third-party plugins incompatible. It is always advised to check plugin compatibility in the Plugin Version Matrix with each new upgrade, and more so for this version.
Follow the detailed Upgrade Guide to complete your upgrade.