Question: I'm a junior .NET developer and our company has a ton of code in their main application. All of our css for the web application is using bootstrap 2.3. I've been assigned the task to migrate from 2.3 to the new 3.0. This update has a ton of major changes. I'm looking for any and all suggestions on how I can make this work efficiently without having to go into each file and change the class. 

Container fluid and row fluid are now just container and fluid. These classes are probably on every single html page in our application. Please help me :)

Answer: 
Bootstrap 3 is a major upgrade. You will have to "manually" update the classes in each file, and in some cases change the structure of your markup. There are some tools that can help..

See:

[Updating Bootstrap to version 3 - what do I have to do?](https://stackoverflow.com/questions/17974998/updating-bootstrap-to-version-3-what-do-i-have-to-do)

<http://upgrade-bootstrap.bootply.com>
Use the find and replace for entire solution.