Adding Debian Jessie Backports Repository [SOLVED]

[RWMills]

I need to install a package that resides in the Debian Jessie Backports Repository. The default repository currently holds version 0.9.5 of Roundcube but I need to install a newer version (pref 1.1.5).

I've noticed the discussions regarding mixing Arm6 and Arm7 packages but don't think this is relevant to Roundcube as it's written in PHP.

According to what I've found/read on the web, all I have to do is:

1) Create a file named /etc/apt/sources.list.d/backports.list.
2) Add the line 'deb ftp://ftp.nl.debian.org/debian jessie-backports main contrib non-free'.
3) apt-get update
4) apt-get install roundcube

apt-get update displays the message:

W: GPG error: ftp://ftp.nl.debian.org jessie-backports InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 8B48AD6246925553 NO_PUBKEY 7638D0442B90D010

Are the packages in the backports repository still available to install?

I'm running Jessie-Lite on an RPi2

Update:

I consider this topic is now solved.
Thanks to DirkS for his help.

[DirkS]

Does http://raspberrypi.stackexchange.com/qu ... debian-org help?

[RWMills]

Does http://raspberrypi.stackexchange.com/qu ... debian-org help?

Had to do it twice (once for each key).

Code: Select all

$ apt-cache policy roundcube
roundcube:
  Installed: (none)
  Candidate: 0.9.5+dfsg1-4.1
  Version table:
     1.1.4+dfsg.1-1~bpo8+1 0
        100 ftp://ftp.nl.debian.org/debian/ jessie-backports/main armhf Packages
     0.9.5+dfsg1-4.1 0
        500 http://mirrordirector.raspbian.org/raspbian/ jessie/main armhf Packages

How to I get apt-get to install the newer version?

Code: Select all

$ apt-get install -t'1.1*' roundcube
Reading package lists... Done
E: The value '1.1*' is invalid for APT::Default-Release as such a release is not available in the sources

[DirkS]

Use

Code: Select all

apt-get install -t jessie-backports roundcube

?
(see http://backports.debian.org/Instructions/)