======Debian add testing repo======
<code - /etc/apt/sources.list.d>
deb http://ftp.nl.debian.org/debian testing main
</code>

<code - /etc/apt/preferences.d/helux>
Package: *
Pin: release a=stable
Pin-Priority: 700

Package: *
Pin: release a=testing
Pin-Priority: 650
</code>

  apt-get update
The upgrade will not upgrade all packages to testing due to the lower priority

  apt-get upgrade
{{tag>linux}}