With the open-source Python community at large dropping Python 2.7 support in their projects, Twisted has decided to do the same. Twisted 20.3.0, the most recently released version, is the final release to offer Python 2.7 support.
Despite the break, the compatibility policy still applies. This means that if your code works with Twisted 20.3 on Python 2.7 and 3.5+, that updating your Twisted on Python 3 up to a theoretical 21.3 would not require changes that would make Python 2.7 + Twisted 20.3 stop working, despite a theoretical Twisted 21.3 not supporting 2.7. (This is, of course, in an ideal situation -- regressions and changes that are excepted from the policy such as security fixes do occur. Testing your applications on Twisted prereleases can help catch places where this happens, so, please do!)
- Amber (HawkOwl)