Every release has a PEP associated with it from 3.6 and above that says about the lifespan of the release with bug fix releases and the time where it enters security fixes only mode. Now 3.4 and 3.5 are in security fixes mode where only security updates for the most part are accepted and the changes are pulled in by the release manager to the respective branches. Also there will be no binary releases and only source releases for security only branches.

Python 3.5.6 security announcement : https://www.python.org/downloads/release/python-356/

> Python 3.5 has now entered "security fixes only" mode, and as such the only changes since Python 3.5.4 are security fixes. Also, Python 3.5.6 has only been released in source code form; no more official binary installers will be produced.

Python 3.8 release lifespan : https://www.python.org/dev/peps/pep-0569/#lifespan

So I have removed 3.4 and 3.5 but it's up to the reviewer to decide if this needs to be backported or not to those branches. I hope I am correct on the above.