As we reported during the launch of MKVToolnix 8.0.0 exactly one month ago, on June 21, 2015, the application received a new graphical user interface (GUI). At the point in time, it was mentioned that MKVToolnix 8.0.0 contained the old user interface as well, which is called mkvmerge GUI and which apparently is still distributed as part of MKVToolnix 8.1.0 and today’s MKVToolnix 8.2.0 maintenance release. However, the next point release, MKVToolnix 8.3.0 will remove it, so users who still have MKVToolnix 8.0.0 or MKVToolnix 8.1.0 installed must upgrade to MKVToolnix 8.2.0 as soon as possible.