The -T command-line switch causes sendmail to set the QueueTimeout option (QueueTimeout) to the value specified. This -T command-line switch is deprecated (as is the QueueTimeout option) in favor of the Timeout option of V8.7 sendmail (Timeout), and might not be included in future versions of sendmail. Note that -oT is still a legal form of shorthand to set the value of the QueueTimeout option.