I have MuseScore 2 and I'm running Mint 17.3. The version of MuseScore in the Software Centre is 1.3. It could be that MuseScore 2 is available in Mint 18. You will need to check.

You can download MuseScore2 from the website as an appimage which can be run from your home page. (or you can install a ppa for v2) There's instructions for downloading and running the appimage on the website, just click on the download link. You can install the appimage by running from the terminal with the option -install and this copies it to the file system and relates musescore .mscz files to the program. I had problems with saving preferences to customise the program but I found that you had to run it as root (Terminal and "sudo musescore") to save preferences but be careful if you run at as root and save a file you've created you will have to do a chown to access it as yourself.

ABC input is available in MuseScore2 via the Plugins menu. You have to check the "abc_import" in the Plugin Manager, Click OK then open the Plugin menu again and the ABC import will be available as a menu item. Unfortunately it doesn't save when you close MuseScore so you have to do both actions every time you run MuseScore.

Accessing the ABC import plugin brings up a text box where you can paste in an abc or there's a button to link it to an abc file in your filestore.