diff --git a/phpBB/adm/style/install_header.html b/phpBB/adm/style/install_header.html
index 6f7f129d39..cfafe7917f 100644
--- a/phpBB/adm/style/install_header.html
+++ b/phpBB/adm/style/install_header.html
@@ -2,6 +2,7 @@
 <html dir="{S_CONTENT_DIRECTION}" lang="{S_USER_LANG}">
 <head>
 <meta charset="utf-8">
+<meta http-equiv="X-UA-Compatible" content="IE=edge">
 <meta name="viewport" content="width=device-width, initial-scale=1" />
 <!-- IF META -->{META}<!-- ENDIF -->
 <title>{PAGE_TITLE}</title>
diff --git a/phpBB/adm/style/install_update_diff.html b/phpBB/adm/style/install_update_diff.html
index 5f80084705..324dc50d05 100644
--- a/phpBB/adm/style/install_update_diff.html
+++ b/phpBB/adm/style/install_update_diff.html
@@ -2,6 +2,7 @@
 <html dir="{S_CONTENT_DIRECTION}" lang="{S_USER_LANG}">
 <head>
 <meta charset="utf-8">
+<meta http-equiv="X-UA-Compatible" content="IE=edge">
 <meta name="viewport" content="width=device-width, initial-scale=1" />
 <!-- IF META -->{META}<!-- ENDIF -->
 <title>{PAGE_TITLE}</title>
diff --git a/phpBB/adm/style/overall_header.html b/phpBB/adm/style/overall_header.html
index ada88edff2..d399c680ee 100644
--- a/phpBB/adm/style/overall_header.html
+++ b/phpBB/adm/style/overall_header.html
@@ -2,6 +2,7 @@
 <html dir="{S_CONTENT_DIRECTION}" lang="{S_USER_LANG}">
 <head>
 <meta charset="utf-8">
+<meta http-equiv="X-UA-Compatible" content="IE=edge">
 <meta name="viewport" content="width=device-width, initial-scale=1" />
 <!-- IF META -->{META}<!-- ENDIF -->
 <title>{PAGE_TITLE}</title>
diff --git a/phpBB/adm/style/simple_header.html b/phpBB/adm/style/simple_header.html
index f62a7a900e..9f47b2052b 100644
--- a/phpBB/adm/style/simple_header.html
+++ b/phpBB/adm/style/simple_header.html
@@ -2,6 +2,7 @@
 <html dir="{S_CONTENT_DIRECTION}" lang="{S_USER_LANG}">
 <head>
 <meta charset="utf-8">
+<meta http-equiv="X-UA-Compatible" content="IE=edge">
 <meta name="viewport" content="width=device-width, initial-scale=1" />
 <!-- IF META -->{META}<!-- ENDIF -->
 <title>{PAGE_TITLE}</title>
diff --git a/phpBB/docs/CHANGELOG.html b/phpBB/docs/CHANGELOG.html
index 89825d612f..6c0e2d33a5 100644
--- a/phpBB/docs/CHANGELOG.html
+++ b/phpBB/docs/CHANGELOG.html
@@ -2,6 +2,7 @@
 <html dir="ltr" lang="en">
 <head>
 <meta charset="utf-8">
+<meta http-equiv="X-UA-Compatible" content="IE=edge">
 <meta name="keywords" content="" />
 <meta name="description" content="phpBB 3.1.x Changelog" />
 <title>phpBB &bull; Changelog</title>
diff --git a/phpBB/docs/FAQ.html b/phpBB/docs/FAQ.html
index 4786d8d796..5f3a425cda 100644
--- a/phpBB/docs/FAQ.html
+++ b/phpBB/docs/FAQ.html
@@ -2,6 +2,7 @@
 <html dir="ltr" lang="en">
 <head>
 <meta charset="utf-8">
+<meta http-equiv="X-UA-Compatible" content="IE=edge">
 <meta name="keywords" content="" />
 <meta name="description" content="phpBB 3.1.x frequently asked questions" />
 <title>phpBB &bull; FAQ</title>
diff --git a/phpBB/docs/INSTALL.html b/phpBB/docs/INSTALL.html
index 2929c7be28..333d367aa7 100644
--- a/phpBB/docs/INSTALL.html
+++ b/phpBB/docs/INSTALL.html
@@ -2,6 +2,7 @@
 <html dir="ltr" lang="en">
 <head>
 <meta charset="utf-8">
+<meta http-equiv="X-UA-Compatible" content="IE=edge">
 <meta name="keywords" content="" />
 <meta name="description" content="phpBB 3.1.x Installation, updating and conversion informations" />
 <title>phpBB &bull; Install</title>
diff --git a/phpBB/docs/README.html b/phpBB/docs/README.html
index 4b85735463..38f74c199a 100644
--- a/phpBB/docs/README.html
+++ b/phpBB/docs/README.html
@@ -2,6 +2,7 @@
 <html dir="ltr" lang="en">
 <head>
 <meta charset="utf-8">
+<meta http-equiv="X-UA-Compatible" content="IE=edge">
 <meta name="keywords" content="" />
 <meta name="description" content="phpBB 3.1.x Readme" />
 <title>phpBB &bull; Readme</title>
diff --git a/phpBB/docs/auth_api.html b/phpBB/docs/auth_api.html
index 27d090c296..960fa76417 100644
--- a/phpBB/docs/auth_api.html
+++ b/phpBB/docs/auth_api.html
@@ -2,6 +2,7 @@
 <html dir="ltr" lang="en">
 <head>
 <meta charset="utf-8">
+<meta http-equiv="X-UA-Compatible" content="IE=edge">
 <meta name="keywords" content="" />
 <meta name="description" content="This is an explanation of how to use the phpBB auth/acl API" />
 <title>phpBB3 &bull; Auth API</title>
diff --git a/phpBB/docs/coding-guidelines.html b/phpBB/docs/coding-guidelines.html
index 26189235ef..eb0fb60de2 100644
--- a/phpBB/docs/coding-guidelines.html
+++ b/phpBB/docs/coding-guidelines.html
@@ -2,6 +2,7 @@
 <html dir="ltr" lang="en">
 <head>
 <meta charset="utf-8">
+<meta http-equiv="X-UA-Compatible" content="IE=edge">
 <meta name="keywords" content="" />
 <meta name="description" content="Ascraeus coding guidelines document" />
 <title>phpBB3 &bull; Coding Guidelines</title>
diff --git a/phpBB/includes/functions.php b/phpBB/includes/functions.php
index 72c0d458c6..8e3f62230a 100644
--- a/phpBB/includes/functions.php
+++ b/phpBB/includes/functions.php
@@ -2401,6 +2401,7 @@ function redirect($url, $return = false, $disable_cd_check = false)
 		echo '<html dir="' . $user->lang['DIRECTION'] . '" lang="' . $user->lang['USER_LANG'] . '">';
 		echo '<head>';
 		echo '<meta charset="utf-8">';
+		echo '<meta http-equiv="X-UA-Compatible" content="IE=edge">';
 		echo '<meta http-equiv="refresh" content="0; url=' . str_replace('&', '&amp;', $url) . '" />';
 		echo '<title>' . $user->lang['REDIRECT'] . '</title>';
 		echo '</head>';
@@ -3997,6 +3998,7 @@ function msg_handler($errno, $msg_text, $errfile, $errline)
 			echo '<html dir="ltr">';
 			echo '<head>';
 			echo '<meta charset="utf-8">';
+			echo '<meta http-equiv="X-UA-Compatible" content="IE=edge">';
 			echo '<title>' . $msg_title . '</title>';
 			echo '<style type="text/css">' . "\n" . '/* <![CDATA[ */' . "\n";
 			echo '* { margin: 0; padding: 0; } html { font-size: 100%; height: 100%; margin-bottom: 1px; background-color: #E4EDF0; } body { font-family: "Lucida Grande", Verdana, Helvetica, Arial, sans-serif; color: #536482; background: #E4EDF0; font-size: 62.5%; margin: 0; } ';
diff --git a/phpBB/includes/functions_download.php b/phpBB/includes/functions_download.php
index 254e65ae3d..328be93046 100644
--- a/phpBB/includes/functions_download.php
+++ b/phpBB/includes/functions_download.php
@@ -108,6 +108,7 @@ function wrap_img_in_html($src, $title)
 	echo '<html>';
 	echo '<head>';
 	echo '<meta charset="utf-8">';
+	echo '<meta http-equiv="X-UA-Compatible" content="IE=edge">';
 	echo '<title>' . $title . '</title>';
 	echo '</head>';
 	echo '<body>';
diff --git a/phpBB/install/database_update.php b/phpBB/install/database_update.php
index 80fd40a944..42cc27e60b 100644
--- a/phpBB/install/database_update.php
+++ b/phpBB/install/database_update.php
@@ -138,6 +138,7 @@ header('Content-type: text/html; charset=UTF-8');
 <html dir="<?php echo $user->lang['DIRECTION']; ?>" lang="<?php echo $user->lang['USER_LANG']; ?>">
 <head>
 <meta charset="utf-8">
+<meta http-equiv="X-UA-Compatible" content="IE=edge">
 
 <title><?php echo $user->lang['UPDATING_TO_LATEST_STABLE']; ?></title>
 
diff --git a/phpBB/install/index.php b/phpBB/install/index.php
index 5c16421499..b5d14f27cf 100644
--- a/phpBB/install/index.php
+++ b/phpBB/install/index.php
@@ -633,6 +633,7 @@ class module
 		echo '<html dir="ltr">';
 		echo '<head>';
 		echo '<meta charset="utf-8">';
+		echo '<meta http-equiv="X-UA-Compatible" content="IE=edge">';
 		echo '<title>' . $lang['INST_ERR_FATAL'] . '</title>';
 		echo '<link href="' . htmlspecialchars($phpbb_admin_path) . 'style/admin.css" rel="stylesheet" type="text/css" media="screen" />';
 		echo '</head>';
diff --git a/phpBB/phpbb/db/driver/driver.php b/phpBB/phpbb/db/driver/driver.php
index 1b49775b32..01dd66cd6e 100644
--- a/phpBB/phpbb/db/driver/driver.php
+++ b/phpBB/phpbb/db/driver/driver.php
@@ -897,6 +897,7 @@ abstract class driver implements driver_interface
 					<html dir="ltr">
 					<head>
 						<meta charset="utf-8">
+						<meta http-equiv="X-UA-Compatible" content="IE=edge">
 						<title>SQL Report</title>
 						<link href="' . htmlspecialchars($phpbb_path_helper->update_web_root_path($phpbb_root_path) . $phpbb_path_helper->get_adm_relative_path()) . 'style/admin.css" rel="stylesheet" type="text/css" media="screen" />
 					</head>
diff --git a/phpBB/styles/prosilver/template/overall_header.html b/phpBB/styles/prosilver/template/overall_header.html
index ff3a6c4100..adb8931210 100644
--- a/phpBB/styles/prosilver/template/overall_header.html
+++ b/phpBB/styles/prosilver/template/overall_header.html
@@ -2,6 +2,7 @@
 <html dir="{S_CONTENT_DIRECTION}" lang="{S_USER_LANG}">
 <head>
 <meta charset="utf-8" />
+<meta http-equiv="X-UA-Compatible" content="IE=edge">
 <meta name="viewport" content="width=device-width, initial-scale=1" />
 {META}
 <title><!-- IF UNREAD_NOTIFICATIONS_COUNT -->({UNREAD_NOTIFICATIONS_COUNT}) <!-- ENDIF --><!-- IF not S_VIEWTOPIC and not S_VIEWFORUM -->{SITENAME} - <!-- ENDIF --><!-- IF S_IN_MCP -->{L_MCP} - <!-- ELSEIF S_IN_UCP -->{L_UCP} - <!-- ENDIF -->{PAGE_TITLE}<!-- IF S_VIEWTOPIC or S_VIEWFORUM --> - {SITENAME}<!-- ENDIF --></title>
diff --git a/phpBB/styles/prosilver/template/simple_header.html b/phpBB/styles/prosilver/template/simple_header.html
index 80f7fd8ebf..3924aa29d9 100644
--- a/phpBB/styles/prosilver/template/simple_header.html
+++ b/phpBB/styles/prosilver/template/simple_header.html
@@ -2,6 +2,7 @@
 <html dir="{S_CONTENT_DIRECTION}" lang="{S_USER_LANG}">
 <head>
 <meta charset="utf-8" />
+<meta http-equiv="X-UA-Compatible" content="IE=edge">
 <meta name="viewport" content="width=device-width, initial-scale=1" />
 {META}
 <title>{SITENAME} &bull; <!-- IF S_IN_MCP -->{L_MCP} &bull; <!-- ELSEIF S_IN_UCP -->{L_UCP} &bull; <!-- ENDIF -->{PAGE_TITLE}</title>
diff --git a/phpBB/styles/prosilver/template/ucp_pm_viewmessage_print.html b/phpBB/styles/prosilver/template/ucp_pm_viewmessage_print.html
index 55d81b4e69..d431561834 100644
--- a/phpBB/styles/prosilver/template/ucp_pm_viewmessage_print.html
+++ b/phpBB/styles/prosilver/template/ucp_pm_viewmessage_print.html
@@ -2,6 +2,7 @@
 <html dir="{S_CONTENT_DIRECTION}" lang="{S_USER_LANG}">
 <head>
 <meta charset="utf-8" />
+<meta http-equiv="X-UA-Compatible" content="IE=edge">
 <meta name="robots" content="noindex" />
 {META}
 <title>{SITENAME} &bull; {PAGE_TITLE}</title>
diff --git a/phpBB/styles/prosilver/template/viewtopic_print.html b/phpBB/styles/prosilver/template/viewtopic_print.html
index f65f1ab542..919c9397e1 100644
--- a/phpBB/styles/prosilver/template/viewtopic_print.html
+++ b/phpBB/styles/prosilver/template/viewtopic_print.html
@@ -2,6 +2,7 @@
 <html dir="{S_CONTENT_DIRECTION}" lang="{S_USER_LANG}">
 <head>
 <meta charset="utf-8" />
+<meta http-equiv="X-UA-Compatible" content="IE=edge">
 <meta name="robots" content="noindex" />
 {META}
 <title>{SITENAME} &bull; {PAGE_TITLE}</title>
diff --git a/phpBB/styles/subsilver2/template/overall_header.html b/phpBB/styles/subsilver2/template/overall_header.html
index 7648edc35a..a4185785e3 100644
--- a/phpBB/styles/subsilver2/template/overall_header.html
+++ b/phpBB/styles/subsilver2/template/overall_header.html
@@ -2,6 +2,7 @@
 <html dir="{S_CONTENT_DIRECTION}" lang="{S_USER_LANG}">
 <head>
 <meta charset="utf-8" />
+<meta http-equiv="X-UA-Compatible" content="IE=edge">
 {META}
 <title><!-- IF UNREAD_NOTIFICATIONS_COUNT -->({UNREAD_NOTIFICATIONS_COUNT}) <!-- ENDIF --><!-- IF not S_VIEWTOPIC and not S_VIEWFORUM -->{SITENAME} - <!-- ENDIF --><!-- IF S_IN_MCP -->{L_MCP} - <!-- ELSEIF S_IN_UCP -->{L_UCP} - <!-- ENDIF -->{PAGE_TITLE}<!-- IF S_VIEWTOPIC or S_VIEWFORUM --> - {SITENAME}<!-- ENDIF --></title>
 
diff --git a/phpBB/styles/subsilver2/template/simple_header.html b/phpBB/styles/subsilver2/template/simple_header.html
index 3abf89719f..2beeac2548 100644
--- a/phpBB/styles/subsilver2/template/simple_header.html
+++ b/phpBB/styles/subsilver2/template/simple_header.html
@@ -2,6 +2,7 @@
 <html dir="{S_CONTENT_DIRECTION}" lang="{S_USER_LANG}">
 <head>
 <meta charset="utf-8" />
+<meta http-equiv="X-UA-Compatible" content="IE=edge">
 {META}
 <title>{SITENAME} &bull; <!-- IF S_IN_MCP -->{L_MCP} &bull; <!-- ELSEIF S_IN_UCP -->{L_UCP} &bull; <!-- ENDIF -->{PAGE_TITLE}</title>
 
diff --git a/phpBB/styles/subsilver2/template/ucp_pm_viewmessage_print.html b/phpBB/styles/subsilver2/template/ucp_pm_viewmessage_print.html
index fd5e390d83..624a6ea8ef 100644
--- a/phpBB/styles/subsilver2/template/ucp_pm_viewmessage_print.html
+++ b/phpBB/styles/subsilver2/template/ucp_pm_viewmessage_print.html
@@ -2,6 +2,7 @@
 <html dir="{S_CONTENT_DIRECTION}" lang="{S_USER_LANG}">
 <head>
 <meta charset="utf-8" />
+<meta http-equiv="X-UA-Compatible" content="IE=edge">
 <meta name="robots" content="noindex" />
 <title>{SITENAME} :: {PAGE_TITLE}</title>
 
diff --git a/phpBB/styles/subsilver2/template/viewtopic_print.html b/phpBB/styles/subsilver2/template/viewtopic_print.html
index 9497fda121..53b38f414e 100644
--- a/phpBB/styles/subsilver2/template/viewtopic_print.html
+++ b/phpBB/styles/subsilver2/template/viewtopic_print.html
@@ -2,6 +2,7 @@
 <html dir="{S_CONTENT_DIRECTION}" lang="{S_USER_LANG}">
 <head>
 <meta charset="utf-8" />
+<meta http-equiv="X-UA-Compatible" content="IE=edge">
 <meta name="robots" content="noindex" />
 <title>{SITENAME} :: {PAGE_TITLE}</title>
 
