Issue 9996: "bd" is a date field it cannot be empty

src/Model/Contact.php

@@ -2579,9 +2579,7 @@ class Contact
 	public static function updateBirthdays()
 	{
 		$condition = [
-			'`bd` != ""
-			AND `bd` > "0001-01-01"
-			AND SUBSTRING(`bd`, 1, 4) != `bdyear`
+			'`bd` > "0001-01-01"
 			AND (`contact`.`rel` = ? OR `contact`.`rel` = ?)
 			AND NOT `contact`.`pending`
 			AND NOT `contact`.`hidden`