diff --git a/public/404.html b/public/404.html
index 23c08dd81..400bc0108 100644
--- a/public/404.html
+++ b/public/404.html
@@ -1,20 +1,14 @@
-<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
-   "http://www.w3.org/TR/html4/loose.dtd">
+<!DOCTYPE html>
 <html>
-<title>Redmine 404 error</title>
-<style>
-body{
-font-family: Trebuchet MS,Georgia,"Times New Roman",serif;
-color:#303030;
-margin:10px;
-}
-h1{
-font-size:1.5em;
-}
-p{
-font-size:0.8em;
-}
-</style>
+<head>
+  <meta charset="utf-8" />
+  <title>Redmine 404 error</title>
+  <style>
+    body {font-family: Trebuchet MS, Georgia, "Times New Roman", serif; color: #303030; margin: 10px;}
+    h1 {font-size:1.5em;}
+    p {font-size:0.8em;}
+  </style>
+</head>
 <body>
   <h1>Page not found</h1>
   <p>The page you were trying to access doesn't exist or has been removed.</p>
diff --git a/public/500.html b/public/500.html
index 588d83bb6..4afdbda68 100644
--- a/public/500.html
+++ b/public/500.html
@@ -1,20 +1,14 @@
-<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
-   "http://www.w3.org/TR/html4/loose.dtd">
+<!DOCTYPE html>
 <html>
-<title>Redmine 500 error</title>
-<style>
-body{
-font-family: Trebuchet MS,Georgia,"Times New Roman",serif;
-color:#303030;
-margin:10px;
-}
-h1{
-font-size:1.5em;
-}
-p{
-font-size:0.8em;
-}
-</style>
+<head>
+  <meta charset="utf-8" />
+  <title>Redmine 500 error</title>
+  <style>
+    body {font-family: Trebuchet MS, Georgia, "Times New Roman", serif; color: #303030; margin: 10px;}
+    h1 {font-size:1.5em;}
+    p {font-size:0.8em;}
+  </style>
+</head>
 <body>
   <h1>Internal error</h1>
   <p>An error occurred on the page you were trying to access.<br />
