Rebuild delta mode

inc/Project.php

@@ -164,6 +164,17 @@ class Project extends PhpObject {
 		return $iLastUpdate;
 	}
 
+	public function getLastMessageId($asConstraints=array()): int {
+		$iLastMsg = 0;
+
+		$asFeedIds = $this->getFeedIds();
+		foreach($asFeedIds as $iFeedId) {
+			$iLastMsg = max($iLastMsg, (new Feed($this->oDb, $iFeedId))->getLastMessageId($asConstraints));
+		}
+
+		return $iLastMsg;
+	}
+
 	public function getMaps() {
 		$sQuery =
 			"SELECT codename, geo_name, min_zoom, max_zoom, attribution ".