diff --git a/lib/certificates/check.js b/lib/certificates/check.js
index 0c239ec..f920aa9 100644
--- a/lib/certificates/check.js
+++ b/lib/certificates/check.js
@@ -4,7 +4,7 @@ const pathHelper = require("../pathHelper");
 const fileNames = require("../fileNames");
 
 module.exports.check = (opts, options) => {
-    var id = opts.certificate && opts.certificate.id || opts.subject;
+    const id = opts.certificate && opts.certificate.id || opts.subject;
     console.log("certificates.check for", opts.subject);
 
     let paths = [