The RETENTION="<retention_category>" option is only applicable if the rule action is ACTION="ARCHIVE_ITEM".

Retention_category is the name of an existing retention category defined in Enterprise Vault. A different retention category may be specified for different rules.

The extract below shows how the option might be specified in the ruleset file. In this example, any messages that satisfy the message attribute filters will be archived and given the retention category, Legal:

<RULE NAME="Example rule2" ACTION="ARCHIVE_ITEM"
  RETENTION="Legal">
	<message attribute filters>
</RULE>