Firefox 57 is easily the best update to come to Firefox ever. Mozilla even named this release "Quantum" because of how dramatically the browser speed improved. Couple that with the complete redesign of Firefox's UI, and you have a pretty dramatic change.
This is a companion discussion topic for the original entry at https://linuxconfig.org/how-to-install-firefox-quantum-on-debian-stretch-linux
Shahnewaz Ahmed
No mention of Sid repos being unstable. As a Linux newbie, I got shafted.
Marco Gaz
this is generallly a bad idea. you will experience a lot of dependency trouble when mixing up debian stable and sid like this. I advice against it!
paulez -> Marco Gaz
I agree, pulling packages from Sid is not recommended at all. It is explained here:
https://wiki.debian.org/DontBreakDebian#Don.27t_make_a_FrankenDebian
Recommended install options for newer versions of Firefox are described at https://wiki.debian.org/Firefox
Me
Why does the author not warn the readers to make a good back up first ?
And why does the author give bad advise, ? or at least warn the readers of the possible consequences, From the Debian wiki: “don’t break debian” :
Don’t suffer from Shiny New Stuff Syndrome
The reason
that Debian Stable is so reliable is because software is extensively
tested and bug-fixed before being included. This means that the most
recent version of software is often not available in the Stable
repositories. But it doesn’t mean that the software is too old to be
useful! Before
attempting to install the newest version of some software from
somewhere other than the Debian Stable repositories, here are some
things to keep in mind: Do a search to find the entire Debian documentation, before trying this.
More :
The reason things can break is because the software
packaged for one Debian release is built to be compatible with the rest
of the software for that release. For example, installing packages from buster on a stretch system could also install newer versions of core libraries including libc6. This results in a system that is not testing or stable but a broken mix of the two.
Repositories that can create a FrankenDebian if used with Debian Stable:
Debian testing release (currently buster) Debian unstable release (also known as sid)
Washington
Tks a lot! I did, just as you said and worked very well!!! Congrats from Brazil!
C Bpunkt
When using the apt preferences file, you should take note that it does
not support comments. Syntax errors (such as attempted comments) may
break your APT without giving meaningful error messages. You can add a
“Explanation: got this stuff from Nick” at the beginning of a stanza if
you want to comment it.
Christian
Additionally you have to add the firefox language pack (firefox-l10n-xx) to /etc/apt/preferences .
Otherwise your language pack will be uninstalled on firefox update (just happened 
Christian
First thank you for this good article, but I got a problem when using
‘Package: *
Pin: release a=stable
Pin-Priority: 1000’ in /etc/apt/preferences
Like this:
apt-cache policy base-files
base-files:
Installiert: 9.9+deb9u2
Installationskandidat: 9.9+deb9u1
Versionstabelle:
10 2
2 Index of /debian sid/main amd64 Packages
*** 9.9+deb9u2 500
500 Index of /debian stretch-updates/main amd64 Packages
100 /var/lib/dpkg/status
9.9+deb9u1 1000
1000 Index of /debian stretch/main amd64 Packages
Because of the ‘1000’ stretch is used before stretch-updates causing a downgrade of several packages.
I change the value to ‘500’ and everything is fine.
Konstantin BIFERT
Thanks for the simple working method ! 