Qt 5.12.4, the fourth patch release of Qt 5.12 LTS, is released today. Qt 5.12.4 release provides a number of bug fixes, as well as performance and other improvements. As an important new item it provides binaries build with OpenSSL 1.1.1, including the new TLS 1.3 functionality.
Compared to Qt 5.12.3, the new Qt 5.12.4 provides around 250 bug fixes. For details of the most important changes, please check the Change files of Qt 5.12.4.
The update to OpenSSL 1.1.1 is important to note for users leveraging OpenSSL in their applications. We wanted to update now as the earlier version of OpenSSL runs out of support at the end of the year and some platforms, such as Android, need the new one even sooner. Unfortunately OpenSSL 1.1 is binary incompatible with 1.0, so users need to switch to the new one and repackage their applications. One important functionality enabled by OpenSSL 1.1 is TLS 1.3 bringing significant cryptography and speed improvements. As part of the change, some old and insecure crypto algorithms have been removed and support for some new crypto algorithms added. For the users not leveraging OpenSSL in their applications, no actions are needed. OpenSSL is not included in a Qt application, unless explicitly so defined by the developer.
Going forward, Qt 5.12 LTS will receive many more patch releases throughout the coming years and we recommend all active developed projects to migrate to Qt 5.12 LTS. Qt 5.9 LTS is currently in ‘Strict’ phase and receives only the selected important bug and security fixes, while Qt 5.12 LTS is currently receiving all the bug fixes. Qt 5.6 Support has ended in March 2019, so all active projects still using Qt 5.6 LTS should migrate to a later version of Qt.
Qt 5.12.4 is now available via the maintenance tool of the online installer. For new installations, please download latest online installer from Qt Account portal or from qt.io Download page. Offline packages are available for commercial users in the Qt Account portal and at the qt.io Download page for open-source users. You can also try out the Commercial evaluation option from the qt.io Download page.
