Support of Qt 5.6 LTS ends in March 2019. If you are still with Qt 5.6 LTS, update to Qt 5.9 LTS or Qt 5.12 LTS is recommended. If you can't update, extended support is available for an additional fee after the standard support ends.
Long term supported releases on Qt are supported for three years, thus the support for Qt 5.6 LTS ends in March 2019. Many users have already migrated to later releases, especially to Qt 5.9 LTS. Soon we have also Qt 5.12 LTS available, so those who have not yet switched to more recent versions of Qt are encouraged to do so now.
Qt 5.6 LTS was the first long-term supported Qt 5 release. During its lifetime it has received three patch releases and provided over 2000 bug fixes compared to the earlier Qt 5.5.1 release. Qt 5.6 LTS has been in the 'Very strict' phase already quite a while and after Qt 5.6.3 release there have been very little commits to the 5.6 branch. Mostly just the critical security fixes. Qt 5.6.3 will remain the last release of the series, as there will not be any more Qt 5.6 patch releases created.
Qt 5.6 LTS has been a good release, but the more recent long-term supported Qt releases are even better. For example Qt 5.9.7, the latest patch release of Qt 5.9 LTS, contains over 3000 bug fixes that are not part of Qt 5.6.3. Currently in 'Strict' phase, Qt 5.9 will still receive new patch releases bringing security updates and other important fixes. The soon-to-be-released Qt 5.12 LTS contains over 2000 bug fixes that are not part of Qt 5.9.7 release - and over 5000 bug fixes more than Qt 5.6.3 release. Of course there are also a lot of great new features as well as performance improvements provided by the new versions of Qt.
If you can not switch to c++11 compiler or use a platform no longer supported after Qt 5.6 LTS, Extended support is available. Especially if your Qt 5.6 LTS based application or device is actively maintained after March 2019, purchasing extended support is highly recommended. Extended support can be purchased both for Standard as well as Premium Support. To learn more about Extended support, please contact our Support team and ask about it.
We also have a couple of webinars lined up with additional information on the topic.
The other webinar and focuses on licensing for versions 5.7 and later, since the obligations of LGPL/GPL v3 differ from what you had to comply with from Qt 5.6 LTS and earlier. Since this is very important, it will air in two two time zones EU and APAC / US, so make sure to sign up and have your licensing questions answered live.