diff --git a/CHANGELOG.md b/CHANGELOG.md
index 846e89a1..c8793bfb 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,7 @@
 - Confirm before exiting edited edit form
 - Display collation at table structure if different from table
 - Ctrl+click in select moves the cursor in modern browsers
+- URL parameter ?ext=pdo to force using PDO
 - PostgreSQL: Display auto_increment of inserted rows
 - PostgreSQL: Display description of system variables
 - PostgreSQL: Avoid warning about crdb_version (bug #924, regression from 5.0.5)
diff --git a/adminer/drivers/mssql.inc.php b/adminer/drivers/mssql.inc.php
index 9e49a3a2..80742ccc 100644
--- a/adminer/drivers/mssql.inc.php
+++ b/adminer/drivers/mssql.inc.php
@@ -11,7 +11,7 @@ $drivers["mssql"] = "MS SQL";
 
 if (isset($_GET["mssql"])) {
 	define('Adminer\DRIVER', "mssql");
-	if (extension_loaded("sqlsrv")) {
+	if (extension_loaded("sqlsrv") && $_GET["ext"] != "pdo") {
 		class Db {
 			public $extension = "sqlsrv", $server_info, $affected_rows, $errno, $error;
 			private $link, $result;
diff --git a/adminer/drivers/mysql.inc.php b/adminer/drivers/mysql.inc.php
index 88d7fe05..669adca4 100644
--- a/adminer/drivers/mysql.inc.php
+++ b/adminer/drivers/mysql.inc.php
@@ -6,7 +6,7 @@ $drivers = array("server" => "MySQL / MariaDB") + $drivers;
 if (!defined('Adminer\DRIVER')) {
 	define('Adminer\DRIVER', "server"); // server - backwards compatibility
 	// MySQLi supports everything, MySQL doesn't support multiple result sets, PDO_MySQL doesn't support orgtable
-	if (extension_loaded("mysqli")) {
+	if (extension_loaded("mysqli") && $_GET["ext"] != "pdo") {
 		class Db extends \MySQLi {
 			public $extension = "MySQLi";
 
diff --git a/adminer/drivers/oracle.inc.php b/adminer/drivers/oracle.inc.php
index bf65a90f..cb07fcb2 100644
--- a/adminer/drivers/oracle.inc.php
+++ b/adminer/drivers/oracle.inc.php
@@ -5,7 +5,7 @@ $drivers["oracle"] = "Oracle (beta)";
 
 if (isset($_GET["oracle"])) {
 	define('Adminer\DRIVER', "oracle");
-	if (extension_loaded("oci8")) {
+	if (extension_loaded("oci8") && $_GET["ext"] != "pdo") {
 		class Db {
 			public $extension = "oci8", $server_info, $affected_rows, $errno, $error;
 			public $_current_db;
diff --git a/adminer/drivers/pgsql.inc.php b/adminer/drivers/pgsql.inc.php
index c29c7b31..5612c5a4 100644
--- a/adminer/drivers/pgsql.inc.php
+++ b/adminer/drivers/pgsql.inc.php
@@ -5,7 +5,7 @@ $drivers["pgsql"] = "PostgreSQL";
 
 if (isset($_GET["pgsql"])) {
 	define('Adminer\DRIVER', "pgsql");
-	if (extension_loaded("pgsql")) {
+	if (extension_loaded("pgsql") && $_GET["ext"] != "pdo") {
 		class Db {
 			public $extension = "PgSQL", $server_info, $affected_rows, $error, $timeout;
 			private $link, $result, $string, $database = true;
diff --git a/adminer/drivers/sqlite.inc.php b/adminer/drivers/sqlite.inc.php
index a4352150..3b9fc0a9 100644
--- a/adminer/drivers/sqlite.inc.php
+++ b/adminer/drivers/sqlite.inc.php
@@ -5,7 +5,7 @@ $drivers["sqlite"] = "SQLite";
 
 if (isset($_GET["sqlite"])) {
 	define('Adminer\DRIVER', "sqlite");
-	if (class_exists("SQLite3")) {
+	if (class_exists("SQLite3") && $_GET["ext"] != "pdo") {
 
 		class SqliteDb {
 			public $extension = "SQLite3", $server_info, $affected_rows, $errno, $error;
diff --git a/adminer/include/bootstrap.inc.php b/adminer/include/bootstrap.inc.php
index 19ec69dc..14b5d54d 100644
--- a/adminer/include/bootstrap.inc.php
+++ b/adminer/include/bootstrap.inc.php
@@ -98,6 +98,7 @@ define(
 	preg_replace('~\?.*~', '', relative_uri()) . '?'
 		. (sid() ? SID . '&' : '')
 		. (SERVER !== null ? DRIVER . "=" . urlencode(SERVER) . '&' : '')
+		. ($_GET["ext"] ? "ext=" . urlencode($_GET["ext"]) . '&' : '')
 		. (isset($_GET["username"]) ? "username=" . urlencode($_GET["username"]) . '&' : '')
 		. (DB != "" ? 'db=' . urlencode(DB) . '&' . (isset($_GET["ns"]) ? "ns=" . urlencode($_GET["ns"]) . "&" : "") : '')
 );
diff --git a/adminer/include/functions.inc.php b/adminer/include/functions.inc.php
index 4e995ed4..d9988f33 100644
--- a/adminer/include/functions.inc.php
+++ b/adminer/include/functions.inc.php
@@ -457,7 +457,7 @@ function set_session($key, $val) {
 function auth_url($vendor, $server, $username, $db = null) {
 	global $drivers;
 	$uri = remove_from_uri(implode("|", array_keys($drivers))
-		. "|username|"
+		. "|username|ext|"
 		. ($db !== null ? "db|" : "")
 		. ($vendor == 'mssql' || $vendor == 'pgsql' ? "" : "ns|") // we don't have access to support() here
 		. session_name())
@@ -466,6 +466,7 @@ function auth_url($vendor, $server, $username, $db = null) {
 	return "$match[1]?"
 		. (sid() ? SID . "&" : "")
 		. ($vendor != "server" || $server != "" ? urlencode($vendor) . "=" . urlencode($server) . "&" : "")
+		. ($_GET["ext"] ? "ext=" . urlencode($_GET["ext"]) . "&" : "")
 		. "username=" . urlencode($username)
 		. ($db != "" ? "&db=" . urlencode($db) : "")
 		. ($match[2] ? "&$match[2]" : "")