You can use the following Bootstrap cdn to replace the Bootstrap version in the code:
Bootstrap Online Editor that allows your Bootstrap code online without the need of a web server, You don't need to use a text editor to edit Bootstrap files on your computer.
This way you can quickly and easily see the Bootstrap running results, With ace editor, any errors or warnings are identified and clear and actionable feedback is provided to help you improve the performance of your code. You can write or paste Bootstrap code like this:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Bootstrap online editor</title>
<!-- Bootstrap -->
<link href="https://cdn.jsdelivr.net/npm/[email protected]/dist/css/bootstrap.min.css" rel="stylesheet">
<!--[if lt IE 9]>
<script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/html5shiv.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/[email protected]/dest/respond.min.js"></script>
<![endif]-->
</head>
<body>
<h1>hello, world</h1>
<script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/jquery.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/js/bootstrap.min.js"></script>
</body>
</html>