Qt 5.12.9 LTS Release has been announced for general availability as a maintenance patch release that comes with a host of bug fixes and improvements.
This release comes with more than 40 bugs fixes and another 50 changes, These improvements include security fixes to SQLite 3rd party components.
Qt 5.12 LTS Release is still officially supported until December 2021 with the next release coming around September to October 2020.
You can find detailed information about all the changes to this Qt version from the official changelog found here. Existing users can update their installations using the maintenance tool. New installations can be downloaded from the Qt Account portal for commercial users or from the Qt download page here for open source community users.