Bootstrap Versions
Bootstrap is the world's most famous free CSS framework.
You can choose between the following versions:
B3
Bootstrap 3 is the most stable version of Bootstrap, and it is still supported by the team for critical bugfixes and documentation changes.
B4
Bootstrap 4 is a newer version of Bootstrap; with new components, faster stylesheet and more responsiveness. However, Internet Explorer 9 and down is not supported.
B5
Bootstrap 5 is the newest version of Bootstrap; with a smooth overhaul. However, Internet Explorer 11 and down is not supported, and jQuery is replaced with vanilla JavaScript.