BS 3 is still very valuable for responsive-site conventions within a team, especially if you use it 'properly' from Sass or LESS source. The main part looking dated at this point is the JS that still relies on jQuery. There're projects like boostrap.native [1] and e.g. ReactBootstrap to deal with that tho.
I'm in no hurry for BS 4 until IE (< Edge) completely dies.
BS 3 is still very valuable for responsive-site conventions within a team, especially if you use it 'properly' from Sass or LESS source. The main part looking dated at this point is the JS that still relies on jQuery. There're projects like boostrap.native [1] and e.g. ReactBootstrap to deal with that tho.
I'm in no hurry for BS 4 until IE (< Edge) completely dies.
[1] https://github.com/thednp/bootstrap.native