bootstrap/site/content/docs/4.3/migration.md

layout	title	description	group	aliases	toc
docs	Migrating to v5	Track and review changes to the Bootstrap source files, documentation, and components to help you migrate from v4 to v5.	migration	/migration/	true

Browser support

See the browser and devices page for details on what is currently supported in Bootstrap 5. Since v4, here's what's changed to our browser support:

• Dropped support for Internet Explorer NN
• Dropped support for Firefox NN - MM
• Dropped support for Safari NN
• Dropped support for iOS Safari NN
• Dropped support for Chrome NN
• Dropped support for Android NN

Sass

Changes to our source Sass files and compiled CSS.

• Removed hover, hover-focus, plain-hover-focus, and hover-focus-active mixins. Use regular CSS syntax for these moving forward. See #28267.
• Todo: Remove previously deprecated mixins
  • float()
  • form-control-mixin()
  • retina-img()
  • text-hide() (also dropped the associated utility class, .text-hide)
  • visibility()
• Todo: New variables?
• Todo: Rearrange forms source files (under scss/forms/)
• Todo: Rearrange grid source files (under scss/grid/)
• Removed print styles and $enable-print-styles variable. Print display classes, however, have remained intact. See #28339.

JavaScript

Changes to our source and compiled JavaScript files.

• Dropped jQuery dependency and rewrote plugins to be in regular JavaScript.

Grid and layout

Changes to any layout tools and our grid system.

• Dropped .media component as it can be built with utility classes. See #28265.
• Todo: Remove position: relative from grid columns
• Todo: Integrate CSS grid into our grid system

Content, Reboot, etc

Changes to Reboot, typography, tables, and more.

• Todo: Make RFS enabled by default

Forms

• Todo: Move forms documentation to it's own top-level section
• Todo: Rearrange source Sass files (under scss/forms/)
• Todo: Combine native and custom checkboxes and radios
• Todo: Rewrite checks to support sizing (via em/font-size or explicit modifier classes)
• Todo: Combine native and custom selects
• Todo: Combine native and custom file and range inputs

Components

Alerts

• Todo: Remove auto-darkening of <hr> elements in .alert-* class variants. <hr>s use rgba() for their color, so these should naturally blend anyway.

Badges

Badges were overhauled to better differentiate themselves from buttons and to better utilize utility classes.

• Todo: Removed and replaced .badge modifier classes with background utility classes (e.g., use .bg-primary instead of .badge-primary)
• Todo: Removed .badge-pill for the .rounded-pill utility class
• Todo: Removed badge's hover and focus styles for a.badge and button.badge.

Utilities

• Todo: Drop .text-hide as it's an antiquated method for hiding text that shouldn't be used anymore
• Todo: Split utilities into property-value utility classes and helpers

Build tools