Bootstrap 4 is on its way and may help Bootstrap remain the king of CSS frameworks.
There are a ton of major changes to Bootstrap and it’s impossible to cover them all in detail here, so here are some of our favorite highlights:
– Improved grid system
– Dropped wells, thumbnails, and panels for cards
– Brand new customization options
– Dropped IE8 support and moved to rem and em units
– Improved documentation
Read about the details at Bootstrap Blog