Which version of Bootstrap should I learn now?

Question

If I want to be a junior front end developer
3/4/5 ???

Answer 1

I suggest you to learn latest, until you master it probably this version will be used the most and maybe even new one will be there.
But when you learn one version,check to see diference between versions, so if you need to work on project with older version you wont have that much problem.

Answer 2

Doesn't matter but always try to use latest.

Answer 3

Thank you for your reply:)