$ sudo apt install ubuntu-touch
[sudo] password for townsend: 
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 ubuntu-touch : Depends: ubuntu-sdk-libs but it is not going to be installed
                Depends: account-plugin-owncloud but it is not going to be installed
                Depends: account-plugin-ubuntuone
                Depends: ciborium but it is not going to be installed
                Depends: dialer-app but it is not going to be installed
                Depends: language-pack-touch-en but it is not going to be installed
                Depends: libqt5gui5-gles but it is not going to be installed
                Depends: messaging-app but it is not going to be installed
                Depends: pay-service but it is not going to be installed
                Depends: qml-module-ubuntu-components-gles but it is not going to be installed
                Depends: qtmir-android but it is not going to be installed
                Depends: qtubuntu-android but it is not going to be installed
                Depends: ubuntu-push-client
                Depends: ubuntu-touch-session but it is not going to be installed
E: Unable to correct problems, you have held broken packages.