This cloud wiki setting specifies the minor version of the database, as set when the database was created or last migrated. Across minor versions, while the server has changed, the database structure should not have fundamentally changed -- this is normally used to indicate that node content html should be regenerated.
Modifying this setting should not make your server unstable, but it may break the migration functionality. You should not modify this, and, instead, use the "cloud-wiki migrate" command if you want to move from one version to another.
You should reboot the server after changing this setting.
This node is a part of the cloud wiki manual.