Hi,

steps to switch an Debian installation from stable to testing:

Modify /etc/apt/sources.list
Replace stable name, for Debian 8, its “Jessie” to “testing”

root@debdev:/etc/apt# sed -e 's/jessie/testing/' /etc/apt/sources.list --in-place=.bak
root@debdev:/etc/apt# apt-get update
root@debdev:/etc/apt# apt-get dist-upgrade

Michael puttygen