MKVToolNix 12.0.0 was released a few days ago. It features one rather important bug fix in the HEVC/h.265 code that can result in invalid files. All users are recommended to upgrade.

MKVToolNix 12.0.0 new features:

• Ctrl+Shift+Space now toggle the selection of the current item in all tree views (multiple selections are allowed).
• chapter editor: added the extension `*.cue` (for cue sheet files) to the “open chapter file” dialog.
• When the CUE sheet includes a global title, it will be automatically used for the title tag when the --title option is empty
• added an option `–no-date` that prevents the “date” field from being written to the segment information headers.
• header editor: added support for editing the “date” segment information field.
• Various bug fixes. See the release note.

How to Install MKVToolNix 12.0.0 in Ubuntu:

The official MKVToolNix Linux repository has made the packages for Ubuntu 16.04, Ubuntu 16.10, and Ubuntu 17.04.

Open terminal via Ctrl+Alt+T or by searching for “Terminal” from start menu, when it opens, run following commands one by one:

1. Add the repository via command:

sudo sh -c 'echo "deb http://mkvtoolnix.download/ubuntu/ $(lsb_release -sc) main" >> /etc/apt/sources.list.d/bunkus.org.list'

2. Download and install the key via command:

wget -q -O - https://mkvtoolnix.download/gpg-pub-moritzbunkus.txt | sudo apt-key add -

3. Finally upgrade the software via Software Updater if you’ve a previous release installed:

Or run commands to install / upgrade MKVToolNix:

sudo apt-get update

sudo apt-get install mkvtoolnix mkvtoolnix-gui