Kleyber,
I have not found a solution for it yet.
I was thinking to install the most recent phpbb in a different folder of the server and
then try to import the entire SQL backup file.
But I guess that all the addons that we have currently installed on our forums, should have
to be ported to the new phpbb version and we may need new versions of them too.
In the meantime, if we could find the right flag to set from phpbb admin panel so we can restore the old and very usefull functionality,
that would be great