--- layout: docs title: Migrating to v5 description: Track and review changes to the Bootstrap source files, documentation, and components to help you migrate from v4 to v5. group: migration aliases: "/migration/" toc: true --- ## 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](https://icons.getbootstrap.com). ### 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. ```diff // 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, $custom-theme-colors); + + // Followed by our default maps + @import "maps"; + // Rest of our imports @import "mixins"; @import "utilities"; @import "root"; @import "reboot"; // etc ``` ### New utilities - Expanded [`font-weight` utilities]({{< docsref "/utilities/text#font-weight-and-italics" >}}) to include `.fw-semibold` for semibold fonts. - Expanded [`border-radius` utilities]({{< docsref "/utilities/borders#sizes" >}}) to include two new sizes, `.rounded-4` and `.rounded-5`, for more options. ### Additional changes - **Introduced new `$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]({{< docsref "/components/offcanvas#responsive" >}}).** 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.]({{< docsref "/content/tables#table-group-dividers" >}}) - **[Scrollspy has been rewritten](https://github.com/twbs/bootstrap/pull/33421) 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 `$tooltip-arrow-color`. - Added `.form-check-reverse` modifier to flip the order of labels and associated checkboxes/radios. - Added [striped columns]({{< docsref "/content/tables#striped-columns" >}}) support to tables via the new `.table-striped-columns` class. For a complete list of changes, [see the v5.2.0 project on GitHub](https://github.com/twbs/bootstrap/projects/32). ## v5.1.0
- **Added experimental support for [CSS Grid layout]({{< docsref "/layout/css-grid" >}}). —** This is a work in progress, and is not yet ready for production use, but you can opt into the new feature via Sass. To enable it, disable the default grid, by setting `$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]({{< docsref "/components/navbar#offcanvas" >}}) with the responsive `.navbar-expand-*` classes and some offcanvas markup. - **Added new [placeholder component]({{< docsref "/components/placeholders/" >}}). —** 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]({{< docsref "/components/collapse#horizontal" >}}). —** 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]({{< docsref "/helpers/stacks/" >}}). Choose from horizontal (`.hstack`) and vertical (`.vstack`) stacks. Add vertical dividers similar to `
` elements with the [new `.vr` helpers]({{< docsref "/helpers/vertical-rule/" >}}). - **Added new global `:root` CSS variables. —** Added several new CSS variables to the `:root` level for controlling `` styles. More are in the works, including across our utilities and components, but for now read up [CSS variables in the Customize section]({{< docsref "/customize/css-variables/" >}}). - **Overhauled color and background utilities to use CSS variables, and added new [text opacity]({{< docsref "/utilities/text#opacity" >}}) and [background opacity]({{< docsref "/utilities/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]({{< docsref "/examples#snippets" >}}). Includes [footers]({{< docsref "/examples/footers/" >}}), [dropdowns]({{< docsref "/examples/dropdowns/" >}}), [list groups]({{< docsref "/examples/list-groups/" >}}), and [modals]({{< docsref "/examples/modals/" >}}). - **Removed unused positioning styles from popovers and tooltips** as these are handled solely by Popper.js. `$tooltip-margin` has been deprecated and set to `null` in the process. Want more information? [Read the v5.1.0 blog post.](https://blog.getbootstrap.com/2021/08/04/bootstrap-5-1-0/)
{{< callout info >}} **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. {{< /callout >}} ## 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]({{< docsref "/getting-started/parcel" >}}). - Added [new Customize section]({{< docsref "/customize/overview" >}}), replacing [v4's Theming page](https://getbootstrap.com/docs/4.6/getting-started/theming/), with new details on Sass, global configuration options, color schemes, CSS variables, and more. - Reorganized all form documentation into [new Forms section]({{< docsref "/forms/overview" >}}), breaking apart the content into more focused pages. - Similarly, updated [the Layout section]({{< docsref "/layout/breakpoints" >}}), 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 `$theme-colors`. Check out how to deal with [Sass maps]({{< docsref "/customize/sass#maps-and-loops" >}}). - Breaking Renamed `color-yiq()` function and related variables to `color-contrast()` as it's no longer related to YIQ color space. [See #30168.](https://github.com/twbs/bootstrap/pull/30168/) - `$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](https://github.com/twbs/bootstrap/pull/28339). - Breaking Dropped `color()`, `theme-color()`, and `gray()` functions in favor of variables. [See #29083](https://github.com/twbs/bootstrap/pull/29083). - Breaking Renamed `theme-color-level()` function to `color-level()` and now accepts any color you want instead of only `$theme-color` colors. [See #29083](https://github.com/twbs/bootstrap/pull/29083) **Watch out:** `color-level()` was later on dropped in `v5.0.0-alpha3`. - Breaking Renamed `$enable-prefers-reduced-motion-media-query` and `$enable-pointer-cursor-for-buttons` to `$enable-reduced-motion` and `$enable-button-pointers` for brevity. - Breaking Removed the `bg-gradient-variant()` mixin. Use the `.bg-gradient` class to add gradients to elements instead of the generated `.bg-gradient-*` classes. - Breaking **Removed previously deprecated mixins:** - `hover`, `hover-focus`, `plain-hover-focus`, and `hover-focus-active` - `float()` - `form-control-mixin()` - `nav-divider()` - `retina-img()` - `text-hide()` (also dropped the associated utility class, `.text-hide`) - `visibility()` - `form-control-focus()` - Breaking Renamed `scale-color()` function to `shift-color()` to avoid collision with Sass's own color scaling function. - `box-shadow` mixins now allow `null` values and drop `none` from multiple arguments. [See #30394](https://github.com/twbs/bootstrap/pull/30394). - The `border-radius()` mixin now has a default value. ## Color system - The color system which worked with `color-level()` and `$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](https://github.com/twbs/bootstrap/pull/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]({{< docsref "/layout/gutters" >}}) (`.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](https://github.com/twbs/bootstrap/pull/28265) and the [flex utilities page for an example]({{< docsref "/utilities/flex#media-object" >}}). - 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. - `$enable-grid-classes` no longer disables the generation of container classes anymore. [See #29146.](https://github.com/twbs/bootstrap/pull/29146) - Updated the `make-col` mixin to default to equal columns without a specified size. ## Content, Reboot, etc - **[RFS]({{< docsref "/getting-started/rfs" >}}) is now enabled by default.** Headings using the `font-size()` mixin will automatically adjust their `font-size` to scale with the viewport. _This feature was previously opt-in with v4._ - Breaking Overhauled our display typography to replace our `$display-*` variables and with a `$display-font-sizes` Sass map. Also removed the individual `$display-*-weight` variables for a single `$display-font-weight` and adjusted `font-size`s. - Added two new `.display-*` heading sizes, `.display-5` and `.display-6`. - **Links are underlined by default** (not just on hover), unless they're part of specific components. - **Redesigned tables** to refresh their styles and rebuild them with CSS variables for more control over styling. - Breaking Nested tables do not inherit styles anymore. - Breaking `.thead-light` and `.thead-dark` are dropped in favor of the `.table-*` variant classes which can be used for all table elements (`thead`, `tbody`, `tfoot`, `tr`, `th` and `td`). - Breaking The `table-row-variant()` mixin is renamed to `table-variant()` and accepts only 2 parameters: `$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](https://github.com/twbs/bootstrap/pull/29135) - Breaking `.text-*` utilities do not add hover and focus states to links anymore. `.link-*` helper classes can be used instead. [See #29267](https://github.com/twbs/bootstrap/pull/29267) - Breaking Dropped `.text-justify` class. [See #29793](https://github.com/twbs/bootstrap/pull/29793) - Breaking ~~`
` 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., `
`).~~ - Reset default horizontal `padding-left` on `