diff --git a/classes/pref_prefs.php b/classes/pref_prefs.php
index 78c66124a..c8843adae 100644
--- a/classes/pref_prefs.php
+++ b/classes/pref_prefs.php
@@ -78,6 +78,15 @@ class Pref_Prefs extends Protected_Handler {
 			$pref_name = db_escape_string($pref_name);
 			$value = db_escape_string($_POST[$pref_name]);
 
+			if ($pref_name == 'DIGEST_PREFERRED_TIME') {
+				if (get_pref($this->link, 'DIGEST_PREFERRED_TIME') != $value) {
+
+					db_query($this->link, "UPDATE ttrss_users SET
+						last_digest_sent = NULL WHERE id = " . $_SESSION['uid']);
+
+				}
+			}
+
 			set_pref($this->link, $pref_name, $value);
 
 		}
diff --git a/include/functions.php b/include/functions.php
index 9eb66de3e..0ef1d013f 100644
--- a/include/functions.php
+++ b/include/functions.php
@@ -2706,7 +2706,9 @@
 			if (get_pref($link, 'DIGEST_ENABLE', $line['id'], false)) {
 				$preferred_ts = strtotime(get_pref($link, 'DIGEST_PREFERRED_TIME', $line['id'], '00:00'));
 
-				if ($preferred_ts && time() >= $preferred_ts) {
+				// try to send digests within 2 hours of preferred time
+				if ($preferred_ts && time() >= $preferred_ts &&
+						time() - $preferred_ts <= 7200) {
 
 					if ($debug) print "Sending digest for UID:" . $line['id'] . " - " . $line["email"] . " ... ";