Bootstrap 4 alpha has been released: http://blog.getboots…tstrap-4-alpha/
I’m wondering how they deal with the printing in Bootstrap 4. 
Good news…
The best think that I read was: Dropped IE8 support and moved to rem and em units. Dropping support for IE8 means we can take advantage of the best parts of CSS without being held back with CSS hacks or fallbacks. Pixels have been swapped for rems and ems where appropriate to make responsive typography and component sizing even easier. If you need IE8 support, keep using Bootstrap 3.
It’s fantastic. They would remove all support to IE. It’s not a browser, it’s a trash and pseudo browser.