Thanks for the suggestion, it worked!
On an ubuntu14 vm I'm currently running a nodebb 1.8.2 coupled with a redis 3.0.6 using php 5.
My plan is to move this forum on a ubuntu16 physical machine running php7.
Is there a procedure to backup/restore the nodeBB ?
Or should I try to find a manual way of transfering my redis DB ?
Saw this threads in the suggested topic
I will give it a try later.
You can also see some details at Moving a NodeBB mongo DB from one server to another.