It's tendentious to describe gevent as deprecated.

Like Twisted, there are many projects that continue to choose to use gevent, and consequently (for either of those libraries) Python 2. They solve real problems, as does the codebase we extracted SuPPort from, and we hope to help these projects rather than shun them.

Additionally, asyncio doesn't provide the same user API that gevent does: automagic task switching. Whether or not you like that API is a separate issue.

Finally, even if a person has no interest in using SuPPort, we hope that it might provide her insights into problems she'll likely encounter when using asyncio (or Tornado or Twisted or eventlet or any evented system.)