I'm starting to have second thoughts about my decision to move to B4. I'm currently troubleshooting the navigation in IE 10 using their example:
https://getbootstrap.com/docs/4.0/examples/jumbotron/
After checking it on IE 10, I noticed that the navigation floats off the viewport edge - particularly the search button at the top right:
https://i.sstatic.net/Ru0kQ.jpg
Shouldn't it be functioning properly on IE10 and above?