Our .travis.yml installs and runs mongo enterprise v3.4 for our CI tests. This prevents CI tests from using features in later versions of the server.
This is perhaps slightly more complicated than just bumping the version number - doing that results in a yum error. I'm sure this is an expected and probably easy problem to fix I just didn't didn't spend the time on it.
Grep the codebase for CXX-1548 and ensure fallout is removed.