diff --git a/src/index.js b/src/index.js
index 7f08852..0a6b9ab 100644
--- a/src/index.js
+++ b/src/index.js
@@ -17,29 +17,29 @@ const LogLevels = {
 let logLevel = LogLevels.error;
 function timestamp() {
   const d = new Date().toISOString();
-  return [d.substr(5, 5), d.substr(11, 8)].join(' ')
+  return [d.slice(5, 5), d.slice(11, 8)].join(' ')
 }
 
 class Logger {
   debug(...args) {
     if (LogLevels.debug > logLevel) return;
     const [format, ...rest] = args;
-    console.debug(timestamp(), "D", util.format(format, ...rest));
+    console.error(timestamp(), "D", util.format(format, ...rest));
   }
   info(...args) {
     if (LogLevels.info > logLevel) return;
     const [format, ...rest] = args;
-    console.debug(timestamp(), "I", util.format(format, ...rest));
+    console.error(timestamp(), "I", util.format(format, ...rest));
   }
   warn(...args) {
     if (LogLevels.warn > logLevel) return;
     const [format, ...rest] = args;
-    console.debug(timestamp(), "W", util.format(format, ...rest));
+    console.error(timestamp(), "W", util.format(format, ...rest));
   }
   error(...args) {
     if (LogLevels.error > logLevel) return;
     const [format, ...rest] = args;
-    console.debug(timestamp(), "E", util.format(format, ...rest));
+    console.error(timestamp(), "E", util.format(format, ...rest));
   }
 }
 
@@ -139,7 +139,7 @@ class Logger {
     /** @type TorStream */
     let tor_stream;
     if (uri.hostname.endsWith('.onion')) {
-      const onion = uri.hostname.substr(0, uri.hostname.length - 6);
+      const onion = uri.hostname.slice(0, uri.hostname.length - 6);
       tor_stream = await circuit.create_onion_stream(onion, uri.port);
     } else {
       tor_stream = await circuit.create_stream(uri.hostname, uri.port);