Here is what to do (Unix style, log in to server first):
Backup your 0.7.1 directory!!!
cd /one/folder/above/moregroupware
cp -R moregroupware moregroupware.bak
Backup your database!!!
mysqldump --add-drop-table -a -u [user] -p [dbname] > ~/mgw071.sql
Get the new release from sourceforge.net.
Delete everything in the more.groupware root folder except(!) data_store, data_cache, config.inc.php and templates_c (remove the contents of the latter).
Unpack the new files from the archive(s).
cd /one/folder/above/moregroupware
tar xzf moregroupware-core-0.7.2.tar.gz
Unpack addon archive(s) as needed.
Now edit config.inc.php.
Adjust the following lines to fit:
$appconf['mgw_version_number'] = '0.7.2';
$appconf['mgw_version'] = '0.7.2 - Europe / Update';
Open up your browser and log in to more.groupware as admin, the general module is updated automatically.
Log in as admin again, the update for the overview module is done.
If you run into trouble when logging in (error message about a missing column in mgw_news), manually change the URL in your browser's address bar to point to the news module. This will update the news module and the error should disappear.
Now go to every installed module as admin to call the update procedure.
If all is up and running, you can safely delete the backup files and the SQL dump created in steps 1 and 2.
If you run into trouble, you can revert back to the old release by removing the new moregroupware directory, moving back the backup dir and just piping the backup SQL into the database:
rm -ri moregroupware
mv -i moregroupware.bak moregroupware
mysql -u [user] -p -e "DROP DATABASE [dbname]"
mysql -u [user] -p -e "CREATE DATABASE [dbname]"
mysql -u [user] -p [dbname] < mgw071.sql