Bootstrap 5.3 introduces several key differences compared to previous versions, particularly when compared to Bootstrap 4 and earlier. Here are some of the most significant changes:

1. JavaScript Framework

• Bootstrap 5.3 and 5.x: These versions have moved away from jQuery, using vanilla JavaScript instead. This change makes Bootstrap lighter and more modern, improving performance and compatibility with modern browsers.

• Previous Versions (3 & 4): These versions relied heavily on jQuery for interactive components.

2. Grid System and Layout

• Bootstrap 5.3: Utilizes Flexbox for layout management, providing a more flexible and responsive grid system. This allows for easier customization and better support for modern web design patterns.

• Previous Versions: While also responsive, earlier versions did not leverage Flexbox as extensively.