In the early 2017 Bootstrap 4 is going to be officially released. At this moment we can download and play around with alpha version, so we can compare with current 3.3.7 version. Bootstrap is my CSS framework of choice and I use it in almost every project. It increases the speed of development by providing predefined CSS components and it’s cross-browser support. What’s going to be new in version 4 ?
Bootstrap 4 is going to use more features of HTML5/CSS3. At the times when v3 has been released, not everything were supported by all browsers. In addition, IE8 was still in use, but with the v4 IE8 support will be dropped.
The jQuery Affix plugin will be remove, instead, please use position:sticky, which will be supported by all browsers – except Edge, however, I’m hoping that it will be catch up soon.
The Glyphicons will be removed, so you might need to include some third party icons, like Font Awesome.
Instead of panels and thumbnails, there will be new type of component, cards. Wrapped by .card-columns class, can be organised into masonry-like layout, without using any JS plugin! But this won’t work on IE9 and below.
There are also changes in classes naming, for example .img-responsive into .img-fluid, .btn-default into .btn-secondary, and the grid system also has many differences in naming.
Please review the migration guide https://v4-alpha.getbootstrap.com/migration/ to know full list of differences between Bootstrap 3 and 4.