Compatibility Twitter Bootstrap 3, the feasibility of moving to a new version

Question

css

A little resentment. Twitter Bootstrap 3 is highly recommended. But it is so raw that it is even scary. Here is an example, a login form: examples.getbootstrap.com/signin/index.html It's crooked... The input-block-level class, which is used 2 times on the page, is excluded from the css file. They don't even check the campaign before publishing ...

And 2 questions:

1. Is backward compatibility guaranteed, that is, the work of the new version of the framework with the old site without redesigning the site?
2. In what cases is it advisable to update the current version of the framework? Approximately how many alterations will there be, how long will it take for an average page?

Answer 1

1. No, incompatibility is guaranteed. That's for sure - span* have been replaced (in general, the entire grid has been replaced), all inputs require the form-control class, form elements should be inside a div with the form-group class (instead of row) ...
2. If the page already looks good where it needs look good, BS3 won't improve it. Now the framework is changing a lot even after the release of rc1, so the degree of dampness is absolutely unacceptable. I started to make up a side-project with him - after the release of rc1, I had to go through all the pages and everywhere at least something, but redo it.

Answer 2

Personally, I think old projects should be left on 2.3.1, and new ones should be started on 3 RC.
Just the 3rd version will be finally finished while we study it.