Free score writer MuseScore 3 was released a few months ago. Finally the official PPA for MuseScore 3 is available for Ubuntu 18.04, Ubuntu 18.10, and higher.
MuseScore 3 is a new major release that features automatic placement, brand new Mixer and Piano Roll, dark theme, notation improvements, and many other changes.
MuseScore 3 and MuseScore 2.3 can co-exist on one machine. Installation of the MuseScore 3 will create the association with .mscz/.mscx files, but you can keep using both versions of MuseScore on one machine.
How to Install MuseScore 3 via PPA in Ubuntu:
1. Open terminal either via Ctrl+Alt+T keyboard shortcut or by searching for ‘terminal’ from application menu. When it opens, run command to add the PPA:
sudo add-apt-repository ppa:mscore-ubuntu/mscore3-stable
Type user password (no asterisk feedback due to security reason) when it asks and hit Enter.
2. Then install MuseScore 3 via command:
sudo apt install musescore3
Linux Mint 19 needs to refresh package cache by running command
apt update first.
Once installed, launch the software from application menu and enjoy!
To remove the software, run command in terminal:
sudo apt remove --autoremove musescore3
To remove the PPA, go to Software & Updates -> Other Software tab.