Everyone is encouraged to test their code against the beta to help find possible problems before 3.8.0 final is released in October.
On Travis CI,
3.8-dev currently uses Python 3.8.0b3+. This is a great way to test third-party code against the beta, please add it to your project today!
See also https://snarky.ca/how-to-use-your-project-travis-to-help-test-python-itself/ which was about
3.6-dev and more-or-less also applies to
Python 3.7 and up need Xenial or Bionic on Travis, see https://docs.travis-ci.com/user/languages/python/#python-37-and-higher