The following old example shows a major release change from 6 to 7.
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When required, say an upgrade from 6 to 7, references with "owncloud6" in this file must be changed to "owncloud7". '''DO NOT''' change the "version". The changes can be made with a text editor or the following handy Linux command. The command looks through the "restored" config.php file in the new ownCloud7 ownCloud 7 upgrade instance, for occurrences of owncloud6 and changes them to owncloud7.
sed -i 's/owncloud6/owncloud7/g' /var/hda/web-apps/owncloud7/html/config/config.php