> I would have loved if they kept the CSS classes same between different versions. I'm not great with CSS either but I recently had to implement some very basi

> I would have loved if they kept the CSS classes same between different versions. I'm not great with CSS either but I recently had to implement some very basic Bootstrap functionality in an environment that required Bootstrap 2 (sorry everyone), and FWIW I thought it actually helped that class names were different because it made it very obvious that I was working with a completely different release than most guides were written for, so I expected breaking changes, and any searches I did do for the "old" names gave me correct results. So in that sense, different class names as a type of "version locking" does make sense I guess -- and it perhaps also stops people from lazily just installing a breaking version of Bootstrap and expect it to work.