Hi everyone,

As mentioned in http://twistedmatrix.com/pipermail/twisted-python/2015-March/029258.html , Twisted is removing Python 2.6 support. As such, I would like to announce that 15.3 will be the last release with 2.6 support. After this release, the Python 2.6 buildbots will be removed from the 'supported' list and most likely retired.

This will remove all buildbot coverage of OS X and RHEL/CentOS. As I've been taking point on the buildbots recently, I'm going to be deploying a new CentOS 7 buildslave which will provide coverage of that platform. That just leaves OS X uncovered -- so if you would like to donate buildslaves for this, please send me an email.

Amber "Hawkie" Brown
GPG: https://keybase.io/hawkowl

I don't think that we covered terrible well why we are dropping support. So I'm going to give my take on this, and if

We want Twisted to be available in all kinds of environments. Since it's Twisted's job to let your program talk to the outside world, it's pretty important for you to be able to upgrade it wherever. Heck, we still support Windows XP! Plus, while occasionally annoying, Python 2.6 doesn't impose a significant maintenance burden. So superficially it would seem that we would totally support Python 2.6.

However, Python 2.6 is unsupported by the upstream Python maintainers, and given the increasingly hostile threat landscape, inconveniencing ourselves even a little bit to provide the false impression that Python 2.6 is a "supported" environment where doing new development is OK is not worthwhile.

It's true that Windows XP is a worse security risk, but the difference between XP and 2.6 is that we support Windows XP may bean immutable fact of access to some hardware. According to <http://store.steampowered.com/hwsurvey>, roughly 3% of gamers still use Windows XP, and there's no way for someone writing a Steam game to deliver an OS upgrade along with it, because they don't have access to that environment. The best we can do there is hope that those people eventually buy new computers.

However, if you're delivering software into a Python 2.6 environment, unless it's an embedded environment without support for 2.7, it is at least to some degree under the "your" control (by "your" I mean the software author, which may be an organization where a particular individual who wants to use Twisted doesn't have a say). The only such environment I am aware of is Sublime Text 2, which unfortunately did not upgrade to Python 2.7, but Sublime Text 3, which supports Python 3.3, has been out for over 2 years now.

That said, discontinuing Python 2.6 support in this way - simply removing the buildbots and letting people using it on 2.6 eventually start getting syntax errors when they try to import some random module doesn't help to communicate this intent very well.

To that end, I'd like to propose that we follow suit with the Cryptography project, and emit a DeprecationWarning in 15.3. When you 'pip install cryptography' into a 2.6 environment today, it says:

I don't think it would be worthwhile to do this in every possible unsupported / de-supported environment, but this affects a particularly large audience, many of whom may be ignorant of the issues at stake. <https://caremad.io/2015/04/a-year-of-pypi-downloads/> indicates that roughly 10% of Python users are still stuck on some version of Python 2.6; hopefully Cryptography will be exerting some subtle pressure to get those numbers down.