Qt 5.6 went into beta back in December while originally the official Qt 5.6.0 release was supposed to happen on 8 December. As of right now, Qt 5.6 is running four months behind schedule and Qt 5.7's release schedule is going on concurrently to try to avoid further delays to the Qt5 rhythm.
Qt 5.6 RC1 details were posted to blog.qt.io. Qt 5.6 features fully rewritten HiDPI support, full Windows 10 support, the removal of WebKit and Qt Quick 1 support, and many other changes.
If all goes according to plan and no last minute blockers turn up, Qt 5.6.0 will hopefully be released on 3 March.