diff --git a/src/messenger/tests/server_side/webim/libs/classes/ThreadTest.php b/src/messenger/tests/server_side/webim/libs/classes/ThreadTest.php
index 9cab8d5e..4932b41f 100644
--- a/src/messenger/tests/server_side/webim/libs/classes/ThreadTest.php
+++ b/src/messenger/tests/server_side/webim/libs/classes/ThreadTest.php
@@ -214,6 +214,7 @@ class ThreadTest extends PHPUnit_Framework_TestCase {
 			'dtmcreated' => time() - 100,
 			'dtmmodified' => time() - 90,
 			'dtmchatstarted' => 0,
+			'dtmclosed' => time(),
 
 			'agentId' => 0,
 			'agentName' => '',
diff --git a/src/messenger/webim/install/dbinfo.php b/src/messenger/webim/install/dbinfo.php
index df15d2b9..8b7a93fa 100644
--- a/src/messenger/webim/install/dbinfo.php
+++ b/src/messenger/webim/install/dbinfo.php
@@ -50,6 +50,8 @@ $dbtables = array(
 		"dtmchatstarted" => "int NOT NULL DEFAULT 0",
 		// Unix timestamp of the last thread modification.
 		"dtmmodified" => "int NOT NULL DEFAULT 0",
+		// Unix timestamp of the moment when the thread was closed.
+		"dtmclosed" => "int NOT NULL DEFAULT 0",
 		// ID of the last thread revision.
 		"lrevision" => "int NOT NULL DEFAULT 0",
 		// State of the thread. It is one of Thread::STATE_* constants.
@@ -268,7 +270,7 @@ $dbtables_indexes = array(
 $memtables = array();
 
 $dbtables_can_update = array(
-	"${mysqlprefix}chatthread" => array("agentId", "userTyping", "agentTyping", "messageCount", "nextagent", "shownmessageid", "userid", "userAgent", "groupid", "dtmchatstarted", "invitationstate"),
+	"${mysqlprefix}chatthread" => array("agentId", "userTyping", "agentTyping", "messageCount", "nextagent", "shownmessageid", "userid", "userAgent", "groupid", "dtmchatstarted", "dtmclosed", "invitationstate"),
 	"${mysqlprefix}chatthreadstatistics" => array("missedthreads", "sentinvitations", "acceptedinvitations", "rejectedinvitations", "ignoredinvitations"),
 	"${mysqlprefix}requestbuffer" => array("requestid", "requestkey", "request"),
 	"${mysqlprefix}chatmessage" => array("agentId", "plugin", "data"),
diff --git a/src/messenger/webim/install/dbperform.php b/src/messenger/webim/install/dbperform.php
index 9262ecb4..81056a56 100644
--- a/src/messenger/webim/install/dbperform.php
+++ b/src/messenger/webim/install/dbperform.php
@@ -109,6 +109,11 @@ if ($act == "silentcreateall") {
 			runsql("update ${mysqlprefix}chatthread set dtmchatstarted = dtmcreated", $link);
 		}
 
+		if (in_array("${mysqlprefix}chatthread.dtmclosed", $absent_columns)) {
+			runsql("ALTER TABLE ${mysqlprefix}chatthread ADD dtmclosed int NOT NULL DEFAULT 0 AFTER dtmmodified", $link);
+			runsql("update ${mysqlprefix}chatthread set dtmclosed = dtmmodified", $link);
+		}
+
 		if (in_array("${mysqlprefix}chatthread.agentTyping", $absent_columns)) {
 			runsql("ALTER TABLE ${mysqlprefix}chatthread ADD agentTyping int DEFAULT 0", $link);
 		}
diff --git a/src/messenger/webim/libs/classes/thread.php b/src/messenger/webim/libs/classes/thread.php
index ecb300f2..3472d1cc 100644
--- a/src/messenger/webim/libs/classes/thread.php
+++ b/src/messenger/webim/libs/classes/thread.php
@@ -140,6 +140,7 @@ Class Thread {
 	 *  - 'messageCount': count of user's messages related to the thread
 	 *  - 'created': unix timestamp of the thread creation
 	 *  - 'modified': unix timestamp of the thread's last modification
+	 *  - 'closed': unix timestamp of the moment when the thread was closed
 	 *  - 'chatStarted': unix timestamp of related to thread chat started
 	 *  - 'agentId': id of an operator who take part in the chat
 	 *  - 'agentName': name of an operator who take part in the chat
@@ -177,6 +178,7 @@ Class Thread {
 		'created' => 'dtmcreated',
 		'modified' => 'dtmmodified',
 		'chatStarted' => 'dtmchatstarted',
+		'closed' => 'dtmclosed',
 
 		'agentId' => 'agentId',
 		'agentName' => 'agentName',
@@ -369,7 +371,7 @@ Class Thread {
 		$db = Database::getInstance();
 
 		$query = "update {chatthread} set lrevision = :next_revision, " .
-			"dtmmodified = :now, istate = :state_closed " .
+			"dtmmodified = :now, dtmclosed = :now, istate = :state_closed " .
 			"where istate <> :state_closed and istate <> :state_left " .
 			"and ((lastpingagent <> 0 and lastpinguser <> 0 and " .
 			"(ABS(:now - lastpinguser) > :thread_lifetime and " .
@@ -920,6 +922,7 @@ Class Thread {
 		// Close thread if it's not already closed
 		if ($this->state != self::STATE_CLOSED) {
 			$this->state = self::STATE_CLOSED;
+			$this->closed = time();
 			$this->messageCount = $message_count;
 			$this->save();
 		}
diff --git a/src/messenger/webim/libs/classes/thread_processor.php b/src/messenger/webim/libs/classes/thread_processor.php
index c7a60b5b..87592449 100644
--- a/src/messenger/webim/libs/classes/thread_processor.php
+++ b/src/messenger/webim/libs/classes/thread_processor.php
@@ -606,6 +606,7 @@ class ThreadProcessor extends ClientSideProcessor {
 		$thread->userId = $visitor['id'];
 		$thread->userAgent = $user_browser;
 		$thread->state = Thread::STATE_LEFT;
+		$thread->closed = time();
 		$thread->save();
 
 		// Send some messages
diff --git a/src/messenger/webim/libs/invitation.php b/src/messenger/webim/libs/invitation.php
index 64592889..864a473e 100644
--- a/src/messenger/webim/libs/invitation.php
+++ b/src/messenger/webim/libs/invitation.php
@@ -202,13 +202,15 @@ function invitation_reject($visitor_id) {
 		"UPDATE {chatsitevisitor} v, {chatthread} t SET " .
 			"v.threadid = NULL, " .
 			"t.invitationstate = :invitation_rejected, " .
-			"t.istate = :state_closed " .
+			"t.istate = :state_closed, " .
+			"t.dtmclosed = :now " .
 		"WHERE t.threadid = v.threadid " .
 			"AND visitorid = :visitor_id",
 		array(
 			':invitation_rejected' => Thread::INVITATION_REJECTED,
 			':state_closed' => Thread::STATE_CLOSED,
-			':visitor_id' => $visitor_id
+			':visitor_id' => $visitor_id,
+			':now' => time()
 		)
 	);
 }
@@ -239,6 +241,7 @@ function invitation_close_old() {
 		"UPDATE {chatsitevisitor} v, {chatthread} t SET " .
 			"t.invitationstate = :invitation_ignored, " .
 			"t.istate = :state_closed, " .
+			"t.dtmclosed = :now, " .
 			"v.threadid = NULL " .
 		"WHERE t.istate = :state_invited " .
 			"AND t.invitationstate = :invitation_wait " .