bootstrap/migration.md at b342de4fa3734f43ec1aa9ba42a05b824aa79652

mirror of https://github.com/twbs/bootstrap.git synced 2025-11-12 00:05:05 -05:00

Mark Otto 2b16cb921c make some notes for myself

2014-12-23 03:57:55 -08:00

layout	title
page	Migrating to v4.x.x

Summary

For a broader overview, see what's new in the v4.0.0 release announcement.

Dropped IE8 support—v4 is now only IE9+. For sites needing IE8, use v3.
Dropped iOS 6 support.
Added official support for Android v5.0 Lollipop's Browser and WebView. Earlier versions of the Android Browser and WebView remain only unofficially supported.
Switched from px to rem as our primary unit in CSS.
Media queries are now in ems.
Global font-size increased from 14px to 16px.
Dropped panels, thumbnails, and wells for a new component, cards.
Switched from LESS to SCSS for our source CSS files.
Added a new grid tier for ~480px and below.
Dropped Glyphicons icon font.
Refactored nearly all components to use more unnested classes instead of children selectors.
Non-responsive usage of Bootstrap is no longer supported.
Dropped the online Customizer in favor of more extensive setup documentation.
Replaced the separate optional theme with...

This table shows the style changes between v3.x.x and v4.0.0.

We've added new components and changed some existing ones. Here are the new or updated styles.

Component	Description
Cards	New, more flexible component to replace v3's panels, thumbnails, and wells.
New navbar	Replaces the previous navbar with a new, simpler component.
New progress bars	Replaces the old `.progress` `<div>` with a real `<progress>` element.
New table variants
New utility classes

TODO: audit new classes that didn't exist in v3

The following components have been removed in v4.0.0.

TODO: audit classes in v4 that aren't present in v4

The following deprecated Less/SCSS variables have been removed in v4.0.0:

@screen-phone, @screen-tablet, @screen-desktop, @screen-lg-desktop. Use the more abstract $screen-{xs,sm,md,lg,xl}-* variables instead.
@screen-sm, @screen-md, @screen-lg. Use the more clearly named $screen-{xs,sm,md,lg,xl}-min variables instead.
@screen-xs, @screen-xs-min. The extra small breakpoint has no lower bound, so these variables were logically absurd. Reformulate your expression in terms of $screen-xs-max instead.
@grid-float-breakpoint

Removed the min--moz-device-pixel-ratio typo hack for retina media queries
Dropped .hidden and .show because it interferes with jQuery's $(...).hide().
Change buttons' [disabled] to :disabled as IE9+ supports :disabled. However fieldset[disabled] is still necessary because native disabled fieldsets are still buggy in IE11.

TODO: audit list of stuff in v3 that was marked as deprecated