Note:If you are running a 5.8.x or 5.9.x controller, you should upgrade to 5.8.30 or 5.9.26 (or newer if available at the time you're reading this) prior to upgrading USG.
Changes since v4.4.28 as follows.
Fix crash in speed test encountered when a speed test server refused or abandoned a connection. The same underlying problem exhibited itself in multiple completely different ways. For some, USG went to disconnected in the controller. In other cases, USG was re-adopting repeatedly, or showed up an inform error.
Restore logging of specific error conditions from controller. Recent USG, UAP and USW firmware versions would log "decrypt error" for all error responses from controller.
Fix image/css path issue introduced in 4.4.28 in USG's local web UI.
Upgrade Suricata to 4.0.5. Don't mind the "4.0.0-dev" version string you might see in the logs, it's 4.0.5 and future versions will show the actual version in place of that instead.