diff --git a/docs/manual.rst b/docs/manual.rst
index 1f4ae180c..21613edf7 100644
--- a/docs/manual.rst
+++ b/docs/manual.rst
@@ -2376,6 +2376,7 @@ that will be sent to the tracker. The user-agent is a good way to identify your
 		bool lazy_bitfields;
 		int inactivity_timeout;
 		bool use_dht_as_fallback;
+		bool free_torrent_hashes;
 	};
 
 ``user_agent`` this is the client identification to the tracker.
@@ -2500,6 +2501,14 @@ Default is 10 minutes
 all trackers in its tracker list has failed. Either by an explicit error
 message or a time out.
 
+``free_torrent_hashes`` determines whether or not the torrent's piece hashes
+are kept in memory after the torrent becomes a seed or not. If it is set to
+``true`` the hashes are freed once the torrent is a seed (they're not
+needed anymore since the torrent won't download anything more). If it's set
+to false they are not freed. If they are freed, the torrent_info_ returned
+by get_torrent_info() will return an object that may be incomplete, that
+cannot be passed back to `add_torrent()`_ for instance.
+
 pe_settings
 ===========