Chapter 9. Migrating from Version 3
Version 4 of Bootstrap is a major update. Almost the entire framework has been rewritten to improve code quality, add new components, simplify complex components, and make the tool easier to use overall. We've seen the introduction of new components such as Cards and the removal of a number of basic components that weren't heavily used. In some cases, Cards present a better way of assembling a layout than a number of the removed components. Let's jump into this chapter by showing some specific class and behavioral changes to Bootstrap in version 4.
Browser support
Before we jump into the component details, let's review the new browser support. If you are currently running on version 3 and support some older browsers, you may need to adjust your support level when migrating to Bootstrap 4. For desktop browsers, Internet Explorer version 8 support has been dropped. The new minimum Internet Explorer version that is supported is...