Migrating to v5

Track and review changes to the Bootstrap source files, documentation, and components to help you migrate from v4 to v5.

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v5.3.0-alpha2

If you’re migrating from our previous alpha release of v5.3.0, please reviewing the changes listed below.

CSS variables

Removed several duplicate and unused root CSS variables.

Color modes

Dark mode colors are now derived from our theme colors (e.g., $primary) in Sass, rather than color specific tints or shades (e.g., $blue-300). This allows for a more automated dark mode when customizing the default theme colors.
Added Sass maps for generating theme colors for dark mode text, subtle background, and subtle border.
Snippet examples are now ready for dark mode with updated markup and reduced custom styles.
Added color-scheme: dark to dark mode CSS to change OS level controls like scrollbars
Form validation border-color and text color states now respond to dark mode, thanks to new Sass and CSS variables.
Dropped recently added form control background CSS variables and reassigned the Sass variables to use CSS variables instead. This simplifies the styling across color modes and avoids an issue where form controls in dark mode wouldn’t update properly.
Our box-shadows will once again always stay dark instead of inverting to white when in dark mode.
Improved HTML and JavaScript for our color mode toggle script. The selector for changing the active SVG has been improved, and the markup made more accessible with ARIA attributes.
Improved docs code syntax colors and more across light and dark modes.

Typography

We no longer set a color for $headings-color-dark or --bs-heading-color for dark mode. To avoid several problems of headings within components appearing the wrong color, we’ve set the Sass variable to null and added a null check like we use on the default light mode.

Components

Cards now have a color set on them to improve rendering across color modes.
Added new .nav-underline variant for our navigation with a simpler bottom border under the active nav link. See the docs for an example.
Navs now have new :focus-visible styles that better match our custom button focus styles.

Helpers

Added new .icon-link helper to quickly place and align Bootstrap Icons alongside a textual link. Icon links support our new link utilities, too.
Added new focus ring helper for removing the default outline and setting a custom box-shadow focus ring.

Utilities

Renamed Sass and CSS variables ${color}-text to ${color}-text-emphasis to match their associated utilities.
Added new .link-body-emphasis helper alongside our colored links. This creates a colored link using our color mode responsive emphasis color.
Added new link utilities for link color opacity, underline offset, underline color, and underline opacity. Explore the new links utilities.
CSS variable based border-width utilities have been reverted to set their property directly (as was done prior to v5.2.0). This avoids inheritance issues across nested elements, including tables.
Added new .border-black utility to match our .text-black and .bg-black utilities.
Deprecated Deprecated the .text-muted utility and $text-muted Sass variable. It’s been replaced by .text-body-secondary and $body-secondary-color.

Docs

Examples are now displayed with the appropriate light or dark color mode as dictated by the setting in our docs. Each example has an individual color mode picker.
Improved included JavaScript for live Toast demo.
Added twbs/examples repo contents to the top of the Examples page.

Tooling

Added SCSS testing via True to help test our utilities API and other customizations.
Replaced instances of our bootstrap-npm-starter project with the newer and more complete twbs/examples repo.

For a complete list of changes, see the v5.3.0-alpha2 project on GitHub.

v5.3.0-alpha1

Color modes!

Learn more by reading the new color modes documentation.

Global support for light (default) and dark color modes. Set color mode globally on the :root element, on groups of elements and components with a wrapper class, or directly on components, with data-bs-theme="light|dark". Also included is a new color-mode() mixin that can output a ruleset with the data-bs-theme selector or a media query, depending on your preference.

Deprecated Color modes replace dark variants for components, so .btn-close-white, .carousel-dark, .dropdown-menu-dark, and .navbar-dark are deprecated.
New extended color system. We’ve added new theme colors (but not in $theme-colors) for a more nuanced, system-wide color palette with new secondary, tertiary, and emphasis colors for color and background-color. These new colors are available as Sass variables, CSS variables, and utilities.
We’ve also expanded our theme color Sass variables, CSS variables, and utilities to include text emphasis, subtle background colors, and subtle border colors. These are available as Sass variables, CSS variables, and utilities.

Adds new _variables-dark.scss stylesheet to house dark-mode specific overrides. This stylesheet should be imported immediately after the existing _variables.scss file in your import stack.

diff --git a/scss/bootstrap.scss b/scss/bootstrap.scss
index 8f8296def..449d70487 100644
--- a/scss/bootstrap.scss
+++ b/scss/bootstrap.scss
@@ -6,6 +6,7 @@
 // Configuration
 @import "functions";
 @import "variables";
+@import "variables-dark";
 @import "maps";
 @import "mixins";
 @import "utilities";

CSS variables

Restores CSS variables for breakpoints, though we don’t use them in our media queries as they’re not supported. However, these can be useful in JS-specific contexts.
Per the color modes update, we’ve added new utilities for new Sass CSS variables secondary and tertiary text and background colors, plus {color}-bg-subtle, {color}-border-subtle, and {color}-text-emphasis for our theme colors. These new colors are available through Sass and CSS variables (but not our color maps) with the express goal of making it easier to customize across multiple colors modes like light and dark.
Adds additional variables for alerts, .btn-close, and .offcanvas.
The --bs-heading-color variable is back with an update and dark mode support. First, we now check for a null value on the associated Sass variable, $headings-color, before trying to output the CSS variable, so by default it’s not present in our compiled CSS. Second, we use the CSS variable with a fallback value, inherit, allowing the original behavior to persist, but also allowing for overrides.
Converts links to use CSS variables for styling color, but not text-decoration. Colors are now set with --bs-link-color-rgb and --bs-link-opacity as rgba() color, allowing you to customize the translucency with ease. The a:hover pseudo-class now overrides --bs-link-color-rgb instead of explicitly setting the color property.
--bs-border-width is now being used in more components for greater control over default global styling.
Adds new root CSS variables for our box-shadows, including --bs-box-shadow, --bs-box-shadow-sm, --bs-box-shadow-lg, and --bs-box-shadow-inset.

Components

Alert

Alert variants are now styled via CSS variables.
Deprecated The .alert-variant() mixin is now deprecated. We now use the Sass loop directly to modify the component’s default CSS variables for each variant.

List group

List group item variants are now styled via CSS variables.
Deprecated The .list-group-variant() mixin is now deprecated. We now use the Sass loop directly to modify the component’s default CSS variables for each variant.

Dropdowns

Deprecated The .dropdown-menu-dark class has been deprecated and replaced with data-bs-theme="dark" on the dropdown or any parent element. See the docs for an example.

Close button

Deprecated The .btn-close-white class has been deprecated and replaced with data-bs-theme="dark" on the close button or any parent element. See the docs for an example.

Deprecated The .navbar-dark class has been deprecated and replaced with data-bs-theme="dark" on the navbar or any parent element. See the docs for updated examples.

Progress bars

The markup for progress bars has been updated in v5.3.0. Due to the placement of role and various aria- attributes on the inner .progress-bar element, some screen readers were not announcing zero value progress bars. Now, role="progressbar" and the relevant aria-* attributes are on the outer .progress element, leaving the .progress-bar purely for the visual presentation of the bar and optional label.

While we recommend adopting the new markup for improved compatibility with all screen readers, note that the legacy progress bar structure will continue to work as before.

<!-- Previous markup -->
<div class="progress">
  <div class="progress-bar" role="progressbar" aria-label="Basic example" style="width: 25%" aria-valuenow="25" aria-valuemin="0" aria-valuemax="100"></div>
</div>

<!-- New markup -->
<div class="progress" role="progressbar" aria-label="Basic example" aria-valuenow="25" aria-valuemin="0" aria-valuemax="100">
  <div class="progress-bar" style="width: 25%"></div>
</div>

We’ve also introduced a new .progress-stacked class to more logically wrap multiple progress bars into a single stacked progress bar.

<!-- Previous markup -->
<div class="progress">
  <div class="progress-bar" role="progressbar" aria-label="Segment one" style="width: 15%" aria-valuenow="15" aria-valuemin="0" aria-valuemax="100"></div>
  <div class="progress-bar bg-success" role="progressbar" aria-label="Segment two" style="width: 30%" aria-valuenow="30" aria-valuemin="0" aria-valuemax="100"></div>
  <div class="progress-bar bg-info" role="progressbar" aria-label="Segment three" style="width: 20%" aria-valuenow="20" aria-valuemin="0" aria-valuemax="100"></div>
</div>

<!-- New markup -->
<div class="progress-stacked">
  <div class="progress" role="progressbar" aria-label="Segment one" aria-valuenow="15" aria-valuemin="0" aria-valuemax="100" style="width: 15%">
    <div class="progress-bar"></div>
  </div>
  <div class="progress" role="progressbar" aria-label="Segment two" aria-valuenow="30" aria-valuemin="0" aria-valuemax="100" style="width: 30%">
    <div class="progress-bar bg-success"></div>
  </div>
  <div class="progress" role="progressbar" aria-label="Segment three" aria-valuenow="20" aria-valuemin="0" aria-valuemax="100" style="width: 20%">
    <div class="progress-bar bg-info"></div>
  </div>
</div>

Forms

.form-control is now styled with CSS variables to support color modes. This includes the addition of two new root CSS variables for the default and disabled form control backgrounds.
.form-check and .form-switch components are now built with CSS variables for setting the background-image. The usage here differs from other components in that the various focus, active, etc states for each component aren’t set on the base class. Instead, the states override one variable (e.g., --bs-form-switch-bg).
Floating form labels now have a background-color to fix support for <textarea> elements. Additional changes have been made to also support disabled states and more.
Fixed display of date and time inputs in WebKit based browsers.

Utilities

Deprecated .text-muted will be replaced by .text-body-secondary in v6.

With the addition of the expanded theme colors and variables, the .text-muted variables and utility have been deprecated with v5.3.0. Its default value has also been reassigned to the new --bs-secondary-color CSS variable to better support color modes. It will be removed in v6.0.0.
Adds new .overflow-x, .overflow-y, and several .object-fit-* utilities. The object-fit property is used to specify how an <img> or <video> should be resized to fit its container, giving us a responsive alternative to using background-image for a resizable fill/fit image.
Adds new .fw-medium utility.
Added new .z-* utilities for z-index.
Box shadow utilities (and Sass variables) have been updated for dark mode. They now use --bs-body-color-rgb to generate the rgba() color values, allowing them to easily adapt to color modes based on the specified foreground color.

For a complete list of changes, see the v5.3.0 project on GitHub.

v5.2.0

Refreshed design

Bootstrap v5.2.0 features a subtle design update for a handful of components and properties across the project, most notably through refined border-radius values on buttons and form controls. Our documentation also has been updated with a new homepage, simpler docs layout that no longer collapses sections of the sidebar, and more prominent examples of Bootstrap Icons.

More CSS variables

We’ve updated all our components to use CSS variables. While Sass still underpins everything, each component has been updated to include CSS variables on the component base classes (e.g., .btn), allowing for more real-time customization of Bootstrap. In subsequent releases, we’ll continue to expand our use of CSS variables into our layout, forms, helpers, and utilities. Read more about CSS variables in each component on their respective documentation pages.

Our CSS variable usage will be somewhat incomplete until Bootstrap 6. While we’d love to fully implement these across the board, they do run the risk of causing breaking changes. For example, setting $alert-border-width: var(--bs-border-width) in our source code breaks potential Sass in your own code if you were doing $alert-border-width * 2 for some reason.

As such, wherever possible, we will continue to push towards more CSS variables, but please recognize our implementation may be slightly limited in v5.

New `_maps.scss`

Bootstrap v5.2.0 introduced a new Sass file with _maps.scss. It pulls out several Sass maps from _variables.scss to fix an issue where updates to an original map were not applied to secondary maps that extend them. For example, updates to $theme-colors were not being applied to other theme maps that relied on $theme-colors, breaking key customization workflows. In short, Sass has a limitation where once a default variable or map has been used, it cannot be updated. There’s a similar shortcoming with CSS variables when they’re used to compose other CSS variables.

This is why variable customizations in Bootstrap have to come after @import "functions", but before @import "variables" and the rest of our import stack. The same applies to Sass maps—you must override the defaults before they get used. The following maps have been moved to the new _maps.scss:

$theme-colors-rgb
$utilities-colors
$utilities-text
$utilities-text-colors
$utilities-bg
$utilities-bg-colors
$negative-spacers
$gutters

Your custom Bootstrap CSS builds should now look something like this with a separate maps import.

  // Functions come first
  @import "functions";

  // Optional variable overrides here
+ $custom-color: #df711b;
+ $custom-theme-colors: (
+   "custom": $custom-color
+ );

  // Variables come next
  @import "variables";

+ // Optional Sass map overrides here
+ $theme-colors: map-merge($theme-colors, $custom-theme-colors);
+
+ // Followed by our default maps
+ @import "maps";
+
  // Rest of our imports
  @import "mixins";
  @import "utilities";
  @import "root";
  @import "reboot";
  // etc

New utilities

Expanded font-weight utilities to include .fw-semibold for semibold fonts.
Expanded border-radius utilities to include two new sizes, .rounded-4 and .rounded-5, for more options.

Additional changes

Introduced new $enable-container-classes option. — Now when opting into the experimental CSS Grid layout, .container-* classes will still be compiled, unless this option is set to false. Containers also now keep their gutter values.
Offcanvas component now has responsive variations. The original .offcanvas class remains unchanged—it hides content across all viewports. To make it responsive, change that .offcanvas class to any .offcanvas-{sm|md|lg|xl|xxl} class.
Thicker table dividers are now opt-in. — We’ve removed the thicker and more difficult to override border between table groups and moved it to an optional class you can apply, .table-group-divider. See the table docs for an example.
Scrollspy has been rewritten to use the Intersection Observer API, which means you no longer need relative parent wrappers, deprecates offset config, and more. Look for your Scrollspy implementations to be more accurate and consistent in their nav highlighting.
Popovers and tooltips now use CSS variables. Some CSS variables have been updated from their Sass counterparts to reduce the number of variables. As a result, three variables have been deprecated in this release: $popover-arrow-color, $popover-arrow-outer-color, and $tooltip-arrow-color.
Added new .text-bg-{color} helpers. Instead of setting individual .text-* and .bg-* utilities, you can now use the .text-bg-* helpers to set a background-color with contrasting foreground color.
Added .form-check-reverse modifier to flip the order of labels and associated checkboxes/radios.
Added striped columns support to tables via the new .table-striped-columns class.

For a complete list of changes, see the v5.2.0 project on GitHub.

v5.1.0

Added experimental support for CSS Grid layout. — This is a work in progress, and is not yet ready for production use, but you can opt into the new feature via Sass. To enable it, disable the default grid, by setting $enable-grid-classes: false and enable the CSS Grid by setting $enable-cssgrid: true.
Updated navbars to support offcanvas. — Add offcanvas drawers in any navbar with the responsive .navbar-expand-* classes and some offcanvas markup.
Added new placeholder component. — Our newest component, a way to provide temporary blocks in lieu of real content to help indicate that something is still loading in your site or app.
Collapse plugin now supports horizontal collapsing. — Add .collapse-horizontal to your .collapse to collapse the width instead of the height. Avoid browser repainting by setting a min-height or height.
Added new stack and vertical rule helpers. — Quickly apply multiple flexbox properties to quickly create custom layouts with stacks. Choose from horizontal (.hstack) and vertical (.vstack) stacks. Add vertical dividers similar to <hr> elements with the new .vr helpers.
Added new global :root CSS variables. — Added several new CSS variables to the :root level for controlling <body> styles. More are in the works, including across our utilities and components, but for now read up CSS variables in the Customize section.
Overhauled color and background utilities to use CSS variables, and added new text opacity and background opacity utilities. — .text-* and .bg-* utilities are now built with CSS variables and rgba() color values, allowing you to easily customize any utility with new opacity utilities.
Added new snippet examples based to show how to customize our components. — Pull ready to use customized components and other common design patterns with our new Snippets examples. Includes footers, dropdowns, list groups, and modals.
Removed unused positioning styles from popovers and tooltips as these are handled solely by Popper. $tooltip-margin has been deprecated and set to null in the process.

Want more information? Read the v5.1.0 blog post.

Hey there! Changes to our first major release of Bootstrap 5, v5.0.0, are documented below. They don’t reflect the additional changes shown above.

Dependencies

Dropped jQuery.
Upgraded from Popper v1.x to Popper v2.x.
Replaced Libsass with Dart Sass as our Sass compiler given Libsass was deprecated.
Migrated from Jekyll to Hugo for building our documentation

Browser support

Dropped Internet Explorer 10 and 11
Dropped Microsoft Edge < 16 (Legacy Edge)
Dropped Firefox < 60
Dropped Safari < 12
Dropped iOS Safari < 12
Dropped Chrome < 60

Documentation changes

Redesigned homepage, docs layout, and footer.
Added new Parcel guide.
Added new Customize section, replacing v4’s Theming page, with new details on Sass, global configuration options, color schemes, CSS variables, and more.
Reorganized all form documentation into new Forms section, breaking apart the content into more focused pages.
Similarly, updated the Layout section, to flesh out grid content more clearly.
Renamed “Navs” component page to “Navs & Tabs”.
Renamed “Checks” page to “Checks & radios”.
Redesigned the navbar and added a new subnav to make it easier to get around our sites and docs versions.
Added new keyboard shortcut for the search field: Ctrl + /.

Sass

We’ve ditched the default Sass map merges to make it easier to remove redundant values. Keep in mind you now have to define all values in the Sass maps like $theme-colors. Check out how to deal with Sass maps.
Breaking Renamed color-yiq() function and related variables to color-contrast() as it’s no longer related to YIQ color space. See #30168.
- $yiq-contrasted-threshold is renamed to $min-contrast-ratio.
- $yiq-text-dark and $yiq-text-light are respectively renamed to $color-contrast-dark and $color-contrast-light.
Breaking Media query mixins parameters have changed for a more logical approach.
- media-breakpoint-down() uses the breakpoint itself instead of the next breakpoint (e.g., media-breakpoint-down(lg) instead of media-breakpoint-down(md) targets viewports smaller than lg).
- Similarly, the second parameter in media-breakpoint-between() also uses the breakpoint itself instead of the next breakpoint (e.g., media-between(sm, lg) instead of media-breakpoint-between(sm, md) targets viewports between sm and lg).
Breaking Removed print styles and $enable-print-styles variable. Print display classes are still around. See #28339.
Breaking Dropped color(), theme-color(), and gray() functions in favor of variables. See #29083.
Breaking Renamed theme-color-level() function to color-level() and now accepts any color you want instead of only $theme-color colors. See #29083 Watch out: color-level() was later on dropped in v5.0.0-alpha3.
Breaking Renamed $enable-prefers-reduced-motion-media-query and $enable-pointer-cursor-for-buttons to $enable-reduced-motion and $enable-button-pointers for brevity.
Breaking Removed the bg-gradient-variant() mixin. Use the .bg-gradient class to add gradients to elements instead of the generated .bg-gradient-* classes.
Breaking Removed previously deprecated mixins:
- hover, hover-focus, plain-hover-focus, and hover-focus-active
- float()
- form-control-mixin()
- nav-divider()
- retina-img()
- text-hide() (also dropped the associated utility class, .text-hide)
- visibility()
- form-control-focus()
Breaking Renamed scale-color() function to shift-color() to avoid collision with Sass’s own color scaling function.
box-shadow mixins now allow null values and drop none from multiple arguments. See #30394.
The border-radius() mixin now has a default value.

Color system

The color system which worked with color-level() and $theme-color-interval was removed in favor of a new color system. All lighten() and darken() functions in our codebase are replaced by tint-color() and shade-color(). These functions will mix the color with either white or black instead of changing its lightness by a fixed amount. The shift-color() will either tint or shade a color depending on whether its weight parameter is positive or negative. See #30622 for more details.
Added new tints and shades for every color, providing nine separate colors for each base color, as new Sass variables.
Improved color contrast. Bumped color contrast ratio from 3:1 to 4.5:1 and updated blue, green, cyan, and pink colors to ensure WCAG 2.1 AA contrast. Also changed our color contrast color from $gray-900 to $black.
To support our color system, we’ve added new custom tint-color() and shade-color() functions to mix our colors appropriately.

Grid updates

New breakpoint! Added new xxl breakpoint for 1400px and up. No changes to all other breakpoints.
Improved gutters. Gutters are now set in rems, and are narrower than v4 (1.5rem, or about 24px, down from 30px). This aligns our grid system’s gutters with our spacing utilities.
- Added new gutter class (.g-*, .gx-*, and .gy-*) to control horizontal/vertical gutters, horizontal gutters, and vertical gutters.
- Breaking Renamed .no-gutters to .g-0 to match new gutter utilities.
Columns no longer have position: relative applied, so you may have to add .position-relative to some elements to restore that behavior.
Breaking Dropped several .order-* classes that often went unused. We now only provide .order-1 to .order-5 out of the box.
Breaking Dropped the .media component as it can be easily replicated with utilities. See #28265 and the flex utilities page for an example.
Breaking bootstrap-grid.css now only applies box-sizing: border-box to the column instead of resetting the global box-sizing. This way, our grid styles can be used in more places without interference.
$enable-grid-classes no longer disables the generation of container classes anymore. See #29146.
Updated the make-col mixin to default to equal columns without a specified size.

Content, Reboot, etc

RFS is now enabled by default. Headings using the font-size() mixin will automatically adjust their font-size to scale with the viewport. This feature was previously opt-in with v4.
Breaking Overhauled our display typography to replace our $display-* variables and with a $display-font-sizes Sass map. Also removed the individual $display-*-weight variables for a single $display-font-weight and adjusted font-sizes.
Added two new .display-* heading sizes, .display-5 and .display-6.
Links are underlined by default (not just on hover), unless they’re part of specific components.
Redesigned tables to refresh their styles and rebuild them with CSS variables for more control over styling.
Breaking Nested tables do not inherit styles anymore.
Breaking .thead-light and .thead-dark are dropped in favor of the .table-* variant classes which can be used for all table elements (thead, tbody, tfoot, tr, th and td).
Breaking The table-row-variant() mixin is renamed to table-variant() and accepts only 2 parameters: $color (color name) and $value (color code). The border color and accent colors are automatically calculated based on the table factor variables.
Split table cell padding variables into -y and -x.
Breaking Dropped .pre-scrollable class. See #29135
Breaking .text-* utilities do not add hover and focus states to links anymore. .link-* helper classes can be used instead. See #29267
Breaking Dropped .text-justify class. See #29793
Breaking ~~<hr> elements now use height instead of border to better support the size attribute. This also enables use of padding utilities to create thicker dividers (e.g., <hr class="py-1">).~~
Reset default horizontal padding-left on <ul> and <ol> elements from browser default 40px to 2rem.
Added $enable-smooth-scroll, which applies scroll-behavior: smooth globally—except for users asking for reduced motion through prefers-reduced-motion media query. See #31877

RTL

Horizontal direction specific variables, utilities, and mixins have all been renamed to use logical properties like those found in flexbox layouts—e.g., start and end in lieu of left and right.

Forms

Added new floating forms! We’ve promoted the Floating labels example to fully supported form components. See the new Floating labels page.
Breaking Consolidated native and custom form elements. Checkboxes, radios, selects, and other inputs that had native and custom classes in v4 have been consolidated. Now nearly all our form elements are entirely custom, most without the need for custom HTML.
- .custom-control.custom-checkbox is now .form-check.
- .custom-control.custom-custom-radio is now .form-check.
- .custom-control.custom-switch is now .form-check.form-switch.
- .custom-select is now .form-select.
- .custom-file and .form-file have been replaced by custom styles on top of .form-control.
- .custom-range is now .form-range.
- Dropped native .form-control-file and .form-control-range.
Breaking Dropped .input-group-append and .input-group-prepend. You can now just add buttons and .input-group-text as direct children of the input groups.
The longstanding Missing border radius on input group with validation feedback bug is finally fixed by adding an additional .has-validation class to input groups with validation.
Breaking Dropped form-specific layout classes for our grid system. Use our grid and utilities instead of .form-group, .form-row, or .form-inline.
Breaking Form labels now require .form-label.
Breaking .form-text no longer sets display, allowing you to create inline or block help text as you wish just by changing the HTML element.
Form controls no longer used fixed height when possible, instead deferring to min-height to improve customization and compatibility with other components.
Validation icons are no longer applied to <select>s with multiple.
Rearranged source Sass files under scss/forms/, including input group styles.

Components

Unified padding values for alerts, breadcrumbs, cards, dropdowns, list groups, modals, popovers, and tooltips to be based on our $spacer variable. See #30564.

Accordion

Added new accordion component.

Alerts

Alerts now have examples with icons.
Removed custom styles for <hr>s in each alert since they already use currentColor.

Badges

Breaking Dropped all .badge-* color classes for background utilities (e.g., use .bg-primary instead of .badge-primary).
Breaking Dropped .badge-pill—use the .rounded-pill utility instead.
Breaking Removed hover and focus styles for <a> and <button> elements.
Increased default padding for badges from .25em/.5em to .35em/.65em.

Breadcrumbs

Simplified the default appearance of breadcrumbs by removing padding, background-color, and border-radius.
Added new CSS custom property --bs-breadcrumb-divider for easy customization without needing to recompile CSS.

Buttons

Breaking Toggle buttons, with checkboxes or radios, no longer require JavaScript and have new markup. We no longer require a wrapping element, add .btn-check to the <input>, and pair it with any .btn classes on the <label>. See #30650. The docs for this has moved from our Buttons page to the new Forms section.
Breaking Dropped .btn-block for utilities. Instead of using .btn-block on the .btn, wrap your buttons with .d-grid and a .gap-* utility to space them as needed. Switch to responsive classes for even more control over them. Read the docs for some examples.
Updated our button-variant() and button-outline-variant() mixins to support additional parameters.
Updated buttons to ensure increased contrast on hover and active states.
Disabled buttons now have pointer-events: none;.

Card

Breaking Dropped .card-deck in favor of our grid. Wrap your cards in column classes and add a parent .row-cols-* container to recreate card decks (but with more control over responsive alignment).
Breaking Dropped .card-columns in favor of Masonry. See #28922.
Breaking Replaced the .card based accordion with a new Accordion component.

Carousel

Added new .carousel-dark variant for dark text, controls, and indicators (great for lighter backgrounds).
Replaced chevron icons for carousel controls with new SVGs from Bootstrap Icons.

Close button

Breaking Renamed .close to .btn-close for a less generic name.
Close buttons now use a background-image (embedded SVG) instead of a × in the HTML, allowing for easier customization without the need to touch your markup.
Added new .btn-close-white variant that uses filter: invert(1) to enable higher contrast dismiss icons against darker backgrounds.

Collapse

Removed scroll anchoring for accordions.

Dropdowns

Added new .dropdown-menu-dark variant and associated variables for on-demand dark dropdowns.
Added new variable for $dropdown-padding-x.
Darkened the dropdown divider for improved contrast.
Breaking All the events for the dropdown are now triggered on the dropdown toggle button and then bubbled up to the parent element.
Dropdown menus now have a data-bs-popper="static" attribute set when the positioning of the dropdown is static, or dropdown is in the navbar. This is added by our JavaScript and helps us use custom position styles without interfering with Popper’s positioning.
Breaking Dropped flip option for dropdown plugin in favor of native Popper configuration. You can now disable the flipping behavior by passing an empty array for fallbackPlacements option in flip modifier.
Dropdown menus can now be clickable with a new autoClose option to handle the auto close behavior. You can use this option to accept the click inside or outside the dropdown menu to make it interactive.
Dropdowns now support .dropdown-items wrapped in <li>s.

Jumbotron

Breaking Dropped the jumbotron component as it can be replicated with utilities. See our new Jumbotron example for a demo.

List group

Added new .list-group-numbered modifier to list groups.

Navs and tabs

Added new null variables for font-size, font-weight, color, and :hover color to the .nav-link class.

Navbars

Breaking Navbars now require a container within (to drastically simplify spacing requirements and CSS required).
Breaking The .active class can no longer be applied to .nav-items, it must be applied directly on .nav-links.

Offcanvas

Added the new offcanvas component.

Pagination

Pagination links now have customizable margin-left that are dynamically rounded on all corners when separated from one another.
Added transitions to pagination links.

Popovers

Breaking Renamed .arrow to .popover-arrow in our default popover template.
Renamed whiteList option to allowList.

Spinners

Spinners now honor prefers-reduced-motion: reduce by slowing down animations. See #31882.
Improved spinner vertical alignment.

Toasts

Toasts can now be positioned in a .toast-container with the help of positioning utilities.
Changed default toast duration to 5 seconds.
Removed overflow: hidden from toasts and replaced with proper border-radiuss with calc() functions.

Tooltips

Breaking Renamed .arrow to .tooltip-arrow in our default tooltip template.
Breaking The default value for the fallbackPlacements is changed to ['top', 'right', 'bottom', 'left'] for better placement of popper elements.
Breaking Renamed whiteList option to allowList.

Utilities

Breaking Renamed several utilities to use logical property names instead of directional names with the addition of RTL support:
- Renamed .left-* and .right-* to .start-* and .end-*.
- Renamed .float-left and .float-right to .float-start and .float-end.
- Renamed .border-left and .border-right to .border-start and .border-end.
- Renamed .rounded-left and .rounded-right to .rounded-start and .rounded-end.
- Renamed .ml-* and .mr-* to .ms-* and .me-*.
- Renamed .pl-* and .pr-* to .ps-* and .pe-*.
- Renamed .text-*-left and .text-*-right to .text-*-start and .text-*-end.
Breaking Disabled negative margins by default.
Added new .bg-body class for quickly setting the <body>’s background to additional elements.
Added new position utilities for top, right, bottom, and left. Values include 0, 50%, and 100% for each property.
Added new .translate-middle-x & .translate-middle-y utilities to horizontally or vertically center absolute/fixed positioned elements.
Added new border-width utilities.
Breaking Renamed .text-monospace to .font-monospace.
Breaking Removed .text-hide as it’s an antiquated method for hiding text that shouldn’t be used anymore.
Added .fs-* utilities for font-size utilities (with RFS enabled). These use the same scale as HTML’s default headings (1-6, large to small), and can be modified via Sass map.
Breaking Renamed .font-weight-* utilities as .fw-* for brevity and consistency.
Breaking Renamed .font-italic utility to .fst-italic for brevity and consistency with new .fst-normal utility.
Added .d-grid to display utilities and new gap utilities (.gap) for CSS Grid and flexbox layouts.
Breaking Removed .rounded-sm and rounded-lg, and introduced a new scale of classes, .rounded-0 to .rounded-3. See #31687.
Added new line-height utilities: .lh-1, .lh-sm, .lh-base and .lh-lg. See here.
Moved the .d-none utility in our CSS to give it more weight over other display utilities.
Extended the .visually-hidden-focusable helper to also work on containers, using :focus-within.

Helpers

Breaking Responsive embed helpers have been renamed to ratio helpers with new class names and improved behaviors, as well as a helpful CSS variable.
- Classes have been renamed to change by to x in the aspect ratio. For example, .ratio-16by9 is now .ratio-16x9.
- We’ve dropped the .embed-responsive-item and element group selector in favor of a simpler .ratio > * selector. No more class is needed, and the ratio helper now works with any HTML element.
- The $embed-responsive-aspect-ratios Sass map has been renamed to $aspect-ratios and its values have been simplified to include the class name and the percentage as the key: value pair.
- CSS variables are now generated and included for each value in the Sass map. Modify the --bs-aspect-ratio variable on the .ratio to create any custom aspect ratio.
Breaking “Screen reader” classes are now “visually hidden” classes.
- Changed the Sass file from scss/helpers/_screenreaders.scss to scss/helpers/_visually-hidden.scss
- Renamed .sr-only and .sr-only-focusable to .visually-hidden and .visually-hidden-focusable
- Renamed sr-only() and sr-only-focusable() mixins to visually-hidden() and visually-hidden-focusable().
bootstrap-utilities.css now also includes our helpers. Helpers don’t need to be imported in custom builds anymore.

JavaScript

Dropped jQuery dependency and rewrote plugins to be in regular JavaScript.
Breaking Data attributes for all JavaScript plugins are now namespaced to help distinguish Bootstrap functionality from third parties and your own code. For example, we use data-bs-toggle instead of data-toggle.
All plugins can now accept a CSS selector as the first argument. You can either pass a DOM element or any valid CSS selector to create a new instance of the plugin:
```
const modal = new bootstrap.Modal('#myModal')
const dropdown = new bootstrap.Dropdown('[data-bs-toggle="dropdown"]')
```
popperConfig can be passed as a function that accepts the Bootstrap’s default Popper config as an argument, so that you can merge this default configuration in your way. Applies to dropdowns, popovers, and tooltips.
The default value for the fallbackPlacements is changed to ['top', 'right', 'bottom', 'left'] for better placement of Popper elements. Applies to dropdowns, popovers, and tooltips.
Removed underscore from public static methods like _getInstance() → getInstance().

Migrating to v5

v5.3.0-alpha2

CSS variables

Color modes

Typography

Components

Helpers

Utilities

Docs

Tooling

v5.3.0-alpha1

Color modes!

CSS variables

Components

Alert

List group

Dropdowns

Close button

Navbar

Progress bars

Forms

Utilities

v5.2.0

Refreshed design

More CSS variables

New _maps.scss

New utilities

Additional changes

v5.1.0

Dependencies

Browser support

Documentation changes

Sass

Color system

Grid updates

Content, Reboot, etc

RTL

Forms

Components

Accordion

Alerts

Badges

Breadcrumbs

Buttons

Card

Carousel

Close button

Collapse

Dropdowns

Jumbotron

List group

Navs and tabs

Navbars

Offcanvas

Pagination

Popovers

Spinners

Toasts

Tooltips

Utilities

Helpers

JavaScript

New `_maps.scss`