I’ve had a great deal of recent experience of migrating SME 9.2 to Nethserver. One problem to be aware of is password mismatch in the final stages of the rsync migration. If you use a backup of the SME server, its a little easier - copy /root/.my.cnf to /var/lib/migration/root/.my.cnf - by doing that you avoid a password error when the mysql databases are updated with data from the SME system.
I’ve just (finally) managed a test migration using rsync. For that, I changed the mysql password of the Nethserver to match the mysql password of the SME donor server. To do that, I copied the contents of SME /root/.my.cnf to the Nethserver /root/.my.cnf and /var/lib/nethserver/secrets/mysql, then followed the procedure here:
to change the password to match the new /root/.my.cnf
That seems to have worked and got round the problems I was having in my earlier migration attempts.
Its a long time since I’ve run anything older than SME 9.2, so I don’t know if there will be any other problems migrating an older version.