Translations:Manual:Update.php/18/en

do not purge objectcache table. Normally update.php purges the objectcache (generally contains the parser cache and the messages cache), msg_resource and msg_resource_links (these are used for $loader message caching and are cleared in 1.21 and later) tables in the database, if you don't want to purge this table, use the $nopurge option.