# Dropping Legacy Python support -- Support for Python 3.5 and newer with ITK 5.1

**URL:** https://discourse.itk.org/t/dropping-legacy-python-support-support-for-python-3-5-and-newer-with-itk-5-1/1998
**Category:** Community
**Tags:** python
**Created:** [June 26, 2019, 9:30pm UTC](https://discourse.itk.org/t/dropping-legacy-python-support-support-for-python-3-5-and-newer-with-itk-5-1/1998 "2019-06-26T21:30:51Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![matt.mccormick](https://discourse.itk.org/user_avatar/discourse.itk.org/matt.mccormick/32/7_2.png) [@matt.mccormick](https://discourse.itk.org/u/matt.mccormick)
#### Post date: [June 26, 2019, 9:30pm UTC](https://discourse.itk.org/t/dropping-legacy-python-support-support-for-python-3-5-and-newer-with-itk-5-1/1998/1 "2019-06-26T21:30:52Z")

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ITK 5.0 only supports Python 2.7 on Linux and macOS because of limitations of the C++ compiler required for Python 2.7 on Windows.

Are there any objections to [only supporting Python 3.5](https://github.com/InsightSoftwareConsortium/ITK/pull/1040) and newer on all platforms with ITK 5.1?

As pointed out by @hjmjohnson, many packages in the Scientific Python community only support Python 3.5 and newer in their latest versions, [Python 2 support itself is ending in 2020](https://pythonclock.org/), and this will reduce our maintenance version.

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### Author: ![hjmjohnson](https://discourse.itk.org/user_avatar/discourse.itk.org/hjmjohnson/32/23_2.png) [@hjmjohnson](https://discourse.itk.org/u/hjmjohnson)
#### Post date: [June 27, 2019, 3:06pm UTC](https://discourse.itk.org/t/dropping-legacy-python-support-support-for-python-3-5-and-newer-with-itk-5-1/1998/2 "2019-06-27T15:06:04Z")

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I am fully in support of requiring python 3.5. The focus on a smaller subset environments will allow for using our precious resources for the most benefit.

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### Author: ![matt.mccormick](https://discourse.itk.org/user_avatar/discourse.itk.org/matt.mccormick/32/7_2.png) [@matt.mccormick](https://discourse.itk.org/u/matt.mccormick)
#### Post date: [July 26, 2019, 12:27am UTC](https://discourse.itk.org/t/dropping-legacy-python-support-support-for-python-3-5-and-newer-with-itk-5-1/1998/3 "2019-07-26T00:27:41Z")

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Following up, based on support for this proposal, ITK will only be supporting Python 3 with 5.1.0 and later.

Continuous integration testing on all platforms now uses Python 3. A warning will be issued if a build tries to use Python 2. There are already a few false positive test failures if Python 2 is used on Git `master`, but this will reduce our maintenance burden going forward.