Why is PPA package not taken into account?

Question

I have added the offical Firefox-next PPA:

sudo add-apt-repository ppa:mozillateam/firefox-next
sudo apt-get update
sudo apt-get upgrade

So I get the following config in /etc/apt/sources.list.d/mozillateam-firefox-next-xenial.list

deb http://ppa.launchpad.net/mozillateam/firefox-next/ubuntu xenial main

But the package doesn't upgrade to the PPA version.

Question

How do I fix this?

Answer 1

Policy (before)

$ apt policy firefox
firefox:
  Installed: 48.0+linuxmint1+sarah
  Candidate: 48.0+linuxmint1+sarah
  Version table:
     49.0~b2+build1-0ubuntu0.16.04.1 500
        500 http://ppa.launchpad.net/mozillateam/firefox-next/ubuntu xenial/main amd64 Packages
 *** 48.0+linuxmint1+sarah 700
        700 http://mint-mirror.gwendallebihan.net/packages sarah/upstream amd64 Packages
        100 /var/lib/dpkg/status
     48.0+build2-0ubuntu0.16.04.1 500
        500 http://ftp.u-picardie.fr/mirror/ubuntu/ubuntu xenial-updates/main amd64 Packages
        500 http://security.ubuntu.com/ubuntu xenial-security/main amd64 Packages
     45.0.2+build1-0ubuntu1 500
        500 http://ftp.u-picardie.fr/mirror/ubuntu/ubuntu xenial/main amd64 Packages

APT policy

$ cat /etc/apt/preferences.d/official-extra-repositories.pref
Package: *
Pin: origin build.linuxmint.com
Pin-Priority: 700

Solution

Based on How do I cherry pick packages from a PPA? Add the following rule to /etc/apt/preferences.d/official-extra-repositories.pref in order to prioritize the PPA (highest Pin-Priority will be used):

Package: *firefox*
Pin: release o=LP-PPA-mozillateam-firefox-next
Pin-Priority: 800

Then update and upgrade

sudo apt-get update
sudo apt-get upgrade