diff --git a/src/reverseproxy.js b/src/reverseproxy.js
index b100c68c7..32312e069 100644
--- a/src/reverseproxy.js
+++ b/src/reverseproxy.js
@@ -32,7 +32,6 @@ exports = module.exports = {
 const acme2 = require('./acme2.js'),
     apps = require('./apps.js'),
     assert = require('assert'),
-    async = require('async'),
     blobs = require('./blobs.js'),
     BoxError = require('./boxerror.js'),
     constants = require('./constants.js'),
@@ -658,7 +657,7 @@ async function renewCerts(options, auditSource, progressCallback) {
 
     if (options.domain) appDomains = appDomains.filter(function (appDomain) { return appDomain.domain === options.domain; });
 
-    let progress = 1, renewed = [];
+    let progress = 1, renewedCerts = [];
 
     for (const appDomain of appDomains) {
         progressCallback({ percent: progress, message: `Ensuring certs of ${appDomain.fqdn}` });
@@ -666,7 +665,7 @@ async function renewCerts(options, auditSource, progressCallback) {
 
         const { bundle, renewed } = await ensureCertificate(appDomain.fqdn, appDomain.domain, auditSource);
 
-        if (renewed) renewed.push(appDomain.fqdn);
+        if (renewed) renewedCerts.push(appDomain.fqdn);
 
         if (appDomain.type === 'mail') continue; // mail has no nginx config to check current cert
 
@@ -690,15 +689,15 @@ async function renewCerts(options, auditSource, progressCallback) {
         }
     }
 
-    debug(`renewCerts: Renewed certs of ${JSON.stringify(renewed)}`);
-    if (renewed.length === 0) return;
+    debug(`renewCerts: Renewed certs of ${JSON.stringify(renewedCerts)}`);
+    if (renewedCerts.length === 0) return;
 
-    if (renewed.includes(settings.mailFqdn())) await mail.handleCertChanged();
+    if (renewedCerts.includes(settings.mailFqdn())) await mail.handleCertChanged();
 
     await reload(); // reload nginx if any certs were updated but the config was not rewritten
 
     // restart tls apps on cert change
-    const tlsApps = allApps.filter(app => app.manifest.addons && app.manifest.addons.tls && renewed.includes(app.fqdn));
+    const tlsApps = allApps.filter(app => app.manifest.addons && app.manifest.addons.tls && renewedCerts.includes(app.fqdn));
     for (const app of tlsApps) {
         await apps.restart(app, auditSource);
     }