Bootstrap CSS has just released its first beta release of the new version 4 codebase.
Two years in the making, we finally have our first beta release of Bootstrap 4. In that time, we’ve broken all the things at least twenty-seven times over with nearly 5,000 commits, 650+ files changed, 67,000 lines added, and 82,000 lines deleted. We also shipped six major alpha releases, a trio of official Themes, and even a job board for good measure. Put simply? It’s about time.
Some of the highlights of V4 include:
Moved from Less to Sass.
Bootstrap now compiles faster than ever thanks to Libsass, and we join an increasingly large community of Sass developers.
Flexbox and an improved grid system.
We’ve moved nearly everything to flexbox, added a new grid tier to better target mobile devices, and completely overhauled our source Sass with better variables, mixins, and now maps, too.
Dropped wells, thumbnails, and panels for cards.
Cards are a brand new component to Bootstrap, but they’ll feel super familiar as they do nearly everything wells, thumbnails, and panels did, only better.
Dropped IE8 and IE9 support, dropped older browser versions, and moved to rem units for component sizing to take advantage of newer CSS support.
Aside from our grid, pixels have been swapped for rems and ems where appropriate to make responsive typography and component sizing even easier. Need support for IE8/IE9, Safari 8-, iOS 8-, etc? Keep using Bootstrap 3.
For complete details see the Bootstrap official announcement.