diff --git a/htdocs/core/lib/functions.lib.php b/htdocs/core/lib/functions.lib.php
index c9fed272eaa..886a6473da1 100644
--- a/htdocs/core/lib/functions.lib.php
+++ b/htdocs/core/lib/functions.lib.php
@@ -234,6 +234,25 @@ function isModEnabled($module)
 	//return !empty($conf->$module->enabled);
 }
 
+/**
+ * isDolValidTms check if a timestamp is valid.
+ *
+ * @param  int|string|null $timestamp
+ * @return bool
+ */
+function isDolValidTms($timestamp)
+{
+	if ($timestamp == '') {
+		dol_syslog('Using empty string for a timestamp is deprecated, prefer use of null when calling page '.$_SERVER["PHP_SELF"], LOG_NOTICE);
+		return false;
+	}
+	if (is_null($timestamp) || !is_numeric($timestamp)) {
+		return false;
+	}
+
+	return true;
+}
+
 /**
  * Return a DoliDB instance (database handler).
  *