Qt at a Glance
Qt 5.5 beta should be out this week. Maybe.
Qt 5.4.2 was delayed due to failing tests, which have since been resolved. However, a projected release date is not yet available.
A Qt 4.8.7 release candidate is now available:
The Qt Company's plans for Windows 10 support can be seen here:
http://blog.qt.io/blog/2015/04/29/windows-10-support-in-qt
