Hi Alessandro,
What if I will use bareos I will never get problem between version like happening today with bacula?
difficult to say - I never ran into any upgrade issues with Bareos, but neither with Bacula while I was still using it.
I could use newer bareos client on older bareos director?
I always do it the other way around, i.e. upgrade the director/file daemon and then the clients as time suits. No problems with that so far.
Do you happen to be at FOSDEM? The Bareos team is going to be there, as usual: http://www.bareos.org/en/news/bareos-fosdem-19.html
Cheers,
Peter.