Internet Direct (Indy) Version 9.0.2 Beta
TIdEntityHeaderInfo.Expires
Represents the timestamp when an entity is considered stale.

property Expires: TDateTime;
Description
Expires is a TDateTime property that represents the date and time after which the content of an entity is considered stale. A stale cache entry may not normally be returned by a cache unless it is first validated with the origin server. The presence of an Expires field does not imply that the original resource will change or cease to exist at, before, or after the indicated timestamp value.

Note: A response that includes a CacheControl header with the max-age directive will override the Expires property.