Shows whether the POP3 server supports EXPIRE extension
Shows whether the POP3 server supports EXPIRE extension. The value of the property is valid only after CAPA command has been sent either automatically or from code (see AutoCAPA property description).
From RFC 2449 (Section 6.7, excerpt):
"While POP3 allows clients to leave messages on the server, RFC 1939 [POP3] warns about the problems that may arise from this, and allows servers to delete messages based on site policy. The EXPIRE capability avoids the problems mentioned in RFC 1939, by allowing the server to inform the client as to the policy in effect. The argument to the EXPIRE capability indicates the minimum server retention period, in days, for messages on the server. "For more information see RFC 2449, Section 6.7.