Bootstrap 3 or 4?

Question

Bootstrap

I started to accept bootstrap and the question arose in which of the versions should I understand in depth? Use 3 or immediately learn version 4, so as not to relearn all the changes made later?

Answer 1

Study better while version 3. The difference in the code there will not be colossal to relearn

Answer 2

Oh, don't be afraid to retrain
. We have such a profession here that if you do not study every day, then no one will hire you.

Answer 3

I can't imagine how you can "deeply" study css framework. They were invented for this, not to dig deep, but to quickly do something. If you want to go deeper, learn css.

Answer 4

Bootstrap 4 or Foundation 6

Answer 5

4th version on grids. Considering that they are supported by almost all modern browsers, in my opinion, the answer is obvious)