I have finally managed to upgrade my test blog but, as I trie the backup plugin, I have this message :
'blockquote'WordPress database error: [Incorrect database name 'e.l.m']
SHOW TABLE STATUS FROM
Warning: Invalid argument supplied for foreach() in /var/www/sdb/a/e/e.l.m/blogotest/wp-content/plugins/wp-db-backup.php on line 788 '/blockquote'
And, in fact, when I try to restore that file, my posts are completely "unreadable" (is it correct in English ?) with 2 out of 5 characters changed.
I had done also another backup using the phpmyadmin process and, that, way, it worked fine.
Any idea ?