See comment #35 and the link to the EnableProposed docs.
You need to modify "/etc/apt/sources.list", and "/etc/apt/preferences". (I actually created a separate file "/etc/apt/preferences.d/pin-trusty-proposed" instead, worked the same.)
The two modifications in /etc/apt/ will then allow you to 'apt-get install ubuntu-drivers-common/trusty-proposed'
See comment #35 and the link to the EnableProposed docs.
You need to modify "/etc/apt/ sources. list", and "/etc/apt/ preferences" . (I actually created a separate file "/etc/apt/ preferences. d/pin-trusty- proposed" instead, worked the same.)
The two modifications in /etc/apt/ will then allow you to 'apt-get install ubuntu- drivers- common/ trusty- proposed'