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<section id="nep-29-recommend-python-and-numpy-version-support-as-a-community-policy-standard">
<span id="nep29"></span><h1>NEP 29 — Recommend Python and NumPy version support as a community policy standard<a class="headerlink" href="#nep-29-recommend-python-and-numpy-version-support-as-a-community-policy-standard" title="Link to this heading">#</a></h1>
<dl class="field-list simple">
<dt class="field-odd">Author<span class="colon">:</span></dt>
<dd class="field-odd"><p>Thomas A Caswell <<a class="reference external" href="mailto:tcaswell%40gmail.com">tcaswell<span>@</span>gmail<span>.</span>com</a>>, Andreas Mueller, Brian Granger, Madicken Munk, Ralf Gommers, Matt Haberland <<a class="reference external" href="mailto:mhaberla%40calpoly.edu">mhaberla<span>@</span>calpoly<span>.</span>edu</a>>, Matthias Bussonnier <<a class="reference external" href="mailto:bussonniermatthias%40gmail.com">bussonniermatthias<span>@</span>gmail<span>.</span>com</a>>, Stefan van der Walt <<a class="reference external" href="mailto:stefanv%40berkeley.edu">stefanv<span>@</span>berkeley<span>.</span>edu</a>></p>
</dd>
<dt class="field-even">Status<span class="colon">:</span></dt>
<dd class="field-even"><p>Final</p>
</dd>
<dt class="field-odd">Type<span class="colon">:</span></dt>
<dd class="field-odd"><p>Informational</p>
</dd>
<dt class="field-even">Created<span class="colon">:</span></dt>
<dd class="field-even"><p>2019-07-13</p>
</dd>
<dt class="field-odd">Resolution<span class="colon">:</span></dt>
<dd class="field-odd"><p><a class="reference external" href="https://mail.python.org/pipermail/numpy-discussion/2019-October/080128.html">https://mail.python.org/pipermail/numpy-discussion/2019-October/080128.html</a></p>
</dd>
</dl>
<div class="admonition note">
<p class="admonition-title">Note</p>
<p>This NEP is superseded by the scientific python ecosystem coordination guideline
<a class="reference external" href="https://scientific-python.org/specs/spec-0000/">SPEC 0 — Minimum Supported Versions</a>.</p>
</div>
<section id="abstract">
<h2>Abstract<a class="headerlink" href="#abstract" title="Link to this heading">#</a></h2>
<p>This NEP recommends that all projects across the Scientific
Python ecosystem adopt a common “time window-based” policy for
support of Python and NumPy versions. Standardizing a recommendation
for project support of minimum Python and NumPy versions will improve
downstream project planning.</p>
<p>This is an unusual NEP in that it offers recommendations for
community-wide policy and not for changes to NumPy itself. Since a
common place for SPEEPs (Scientific Python Ecosystem Enhancement
Proposals) does not exist and given NumPy’s central role in the
ecosystem, a NEP provides a visible place to document the proposed
policy.</p>
<p>This NEP is being put forward by maintainers of Matplotlib, scikit-learn,
IPython, Jupyter, yt, SciPy, NumPy, and scikit-image.</p>
</section>
<section id="detailed-description">
<h2>Detailed description<a class="headerlink" href="#detailed-description" title="Link to this heading">#</a></h2>
<p>For the purposes of this NEP we assume semantic versioning and define:</p>
<dl class="simple">
<dt><em>major version</em></dt><dd><p>A release that changes the first number (e.g. X.0.0)</p>
</dd>
<dt><em>minor version</em></dt><dd><p>A release that changes the second number (e.g 1.Y.0)</p>
</dd>
<dt><em>patch version</em></dt><dd><p>A release that changes the third number (e.g. 1.1.Z)</p>
</dd>
</dl>
<p>When a project releases a new major or minor version, we recommend that
they support at least all minor versions of Python
introduced and released in the prior 42 months <em>from the
anticipated release date</em> with a minimum of 2 minor versions of
Python, and all minor versions of NumPy released in the prior 24
months <em>from the anticipated release date</em> with a minimum of 3
minor versions of NumPy.</p>
<p>Consider the following timeline:</p>
<div class="highlight-default notranslate"><div class="highlight"><pre><span></span> <span class="n">Jan</span> <span class="mi">16</span> <span class="n">Jan</span> <span class="mi">17</span> <span class="n">Jan</span> <span class="mi">18</span> <span class="n">Jan</span> <span class="mi">19</span> <span class="n">Jan</span> <span class="mi">20</span>
<span class="o">|</span> <span class="o">|</span> <span class="o">|</span> <span class="o">|</span> <span class="o">|</span>
<span class="o">+++++|+++++++++++|+++++++++++|+++++++++++|+++++++++++|++++++++++++</span>
<span class="o">|</span> <span class="o">|</span> <span class="o">|</span> <span class="o">|</span>
<span class="n">py</span> <span class="mf">3.5.0</span> <span class="n">py</span> <span class="mf">3.6.0</span> <span class="n">py</span> <span class="mf">3.7.0</span> <span class="n">py</span> <span class="mf">3.8.0</span>
<span class="o">|-----------------------------------------></span> <span class="n">Feb19</span>
<span class="o">|-----------------------------------------></span> <span class="n">Dec19</span>
<span class="o">|-----------------------------------------></span> <span class="n">Nov20</span>
</pre></div>
</div>
<p>It shows the 42 month support windows for Python. A project with a
major or minor version release in February 2019 should support Python 3.5 and newer,
a project with a major or minor version released in December 2019 should
support Python 3.6 and newer, and a project with a major or minor version
release in November 2020 should support Python 3.7 and newer.</p>
<p>When this NEP was drafted the Python release cadence was 18 months so a 42
month window ensured that there would always be at least two minor versions of
Python in the window. The window was extended 6 months beyond the anticipated
two-release interval for Python to provide resilience against small
fluctuations / delays in its release schedule.</p>
<p>The Python release cadence increased in <a class="reference external" href="https://peps.python.org/pep-0602/">PEP 0602</a>,
with releases now every 12 months, so there will be 3-4
Python releases in the support window at any time. However, PEP 0602 does not
decrease the support window of Python (18 months of regular full bug-fix
releases and 42 months of as-needed source-only releases). Thus, we do not
expect our users to upgrade Python faster, and our 42 month support window will
cover the same portion of the upstream support of any given Python release.</p>
<p>Because Python minor version support is based only on historical
release dates, a 42 month time window, and a planned project release
date, one can predict with high confidence when a project will be able
to drop any given minor version of Python. This, in turn, could save
months of unnecessary maintenance burden.</p>
<p>If a project releases immediately after a minor version of Python
drops out of the support window, there will inevitably be some
mismatch in supported versions—but this situation should only last
until other projects in the ecosystem make releases.</p>
<p>Otherwise, once a project does a minor or major release, it is
guaranteed that there will be a stable release of all other projects
that, at the source level, support the same set of Python versions
supported by the new release.</p>
<p>If there is a Python 4 or a NumPy 2 this policy will have to be
reviewed in light of the community’s and projects’ best interests.</p>
<section id="support-table">
<h3>Support Table<a class="headerlink" href="#support-table" title="Link to this heading">#</a></h3>
<div class="pst-scrollable-table-container"><table class="table">
<tbody>
<tr class="row-odd"><td><p>Date</p></td>
<td><p>Python</p></td>
<td><p>NumPy</p></td>
</tr>
<tr class="row-even"><td><p>Jan 07, 2020</p></td>
<td><p>3.6+</p></td>
<td><p>1.15+</p></td>
</tr>
<tr class="row-odd"><td><p>Jun 23, 2020</p></td>
<td><p>3.7+</p></td>
<td><p>1.15+</p></td>
</tr>
<tr class="row-even"><td><p>Jul 23, 2020</p></td>
<td><p>3.7+</p></td>
<td><p>1.16+</p></td>
</tr>
<tr class="row-odd"><td><p>Jan 13, 2021</p></td>
<td><p>3.7+</p></td>
<td><p>1.17+</p></td>
</tr>
<tr class="row-even"><td><p>Jul 26, 2021</p></td>
<td><p>3.7+</p></td>
<td><p>1.18+</p></td>
</tr>
<tr class="row-odd"><td><p>Dec 22, 2021</p></td>
<td><p>3.7+</p></td>
<td><p>1.19+</p></td>
</tr>
<tr class="row-even"><td><p>Dec 26, 2021</p></td>
<td><p>3.8+</p></td>
<td><p>1.19+</p></td>
</tr>
<tr class="row-odd"><td><p>Jun 21, 2022</p></td>
<td><p>3.8+</p></td>
<td><p>1.20+</p></td>
</tr>
<tr class="row-even"><td><p>Jan 31, 2023</p></td>
<td><p>3.8+</p></td>
<td><p>1.21+</p></td>
</tr>
<tr class="row-odd"><td><p>Apr 14, 2023</p></td>
<td><p>3.9+</p></td>
<td><p>1.21+</p></td>
</tr>
<tr class="row-even"><td><p>Jun 23, 2023</p></td>
<td><p>3.9+</p></td>
<td><p>1.22+</p></td>
</tr>
<tr class="row-odd"><td><p>Jan 01, 2024</p></td>
<td><p>3.9+</p></td>
<td><p>1.23+</p></td>
</tr>
<tr class="row-even"><td><p>Apr 05, 2024</p></td>
<td><p>3.10+</p></td>
<td><p>1.23+</p></td>
</tr>
<tr class="row-odd"><td><p>Jun 22, 2024</p></td>
<td><p>3.10+</p></td>
<td><p>1.24+</p></td>
</tr>
<tr class="row-even"><td><p>Dec 18, 2024</p></td>
<td><p>3.10+</p></td>
<td><p>1.25+</p></td>
</tr>
<tr class="row-odd"><td><p>Apr 04, 2025</p></td>
<td><p>3.11+</p></td>
<td><p>1.25+</p></td>
</tr>
<tr class="row-even"><td><p>Apr 24, 2026</p></td>
<td><p>3.12+</p></td>
<td><p>1.25+</p></td>
</tr>
</tbody>
</table>
</div>
</section>
<section id="drop-schedule">
<h3>Drop Schedule<a class="headerlink" href="#drop-schedule" title="Link to this heading">#</a></h3>
<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="n">On</span> <span class="nb">next</span> <span class="n">release</span><span class="p">,</span> <span class="n">drop</span> <span class="n">support</span> <span class="k">for</span> <span class="n">Python</span> <span class="mf">3.5</span> <span class="p">(</span><span class="n">initially</span> <span class="n">released</span> <span class="n">on</span> <span class="n">Sep</span> <span class="mi">13</span><span class="p">,</span> <span class="mi">2015</span><span class="p">)</span>
<span class="n">On</span> <span class="n">Jan</span> <span class="mi">07</span><span class="p">,</span> <span class="mi">2020</span> <span class="n">drop</span> <span class="n">support</span> <span class="k">for</span> <span class="n">NumPy</span> <span class="mf">1.14</span> <span class="p">(</span><span class="n">initially</span> <span class="n">released</span> <span class="n">on</span> <span class="n">Jan</span> <span class="mi">06</span><span class="p">,</span> <span class="mi">2018</span><span class="p">)</span>
<span class="n">On</span> <span class="n">Jun</span> <span class="mi">23</span><span class="p">,</span> <span class="mi">2020</span> <span class="n">drop</span> <span class="n">support</span> <span class="k">for</span> <span class="n">Python</span> <span class="mf">3.6</span> <span class="p">(</span><span class="n">initially</span> <span class="n">released</span> <span class="n">on</span> <span class="n">Dec</span> <span class="mi">23</span><span class="p">,</span> <span class="mi">2016</span><span class="p">)</span>
<span class="n">On</span> <span class="n">Jul</span> <span class="mi">23</span><span class="p">,</span> <span class="mi">2020</span> <span class="n">drop</span> <span class="n">support</span> <span class="k">for</span> <span class="n">NumPy</span> <span class="mf">1.15</span> <span class="p">(</span><span class="n">initially</span> <span class="n">released</span> <span class="n">on</span> <span class="n">Jul</span> <span class="mi">23</span><span class="p">,</span> <span class="mi">2018</span><span class="p">)</span>
<span class="n">On</span> <span class="n">Jan</span> <span class="mi">13</span><span class="p">,</span> <span class="mi">2021</span> <span class="n">drop</span> <span class="n">support</span> <span class="k">for</span> <span class="n">NumPy</span> <span class="mf">1.16</span> <span class="p">(</span><span class="n">initially</span> <span class="n">released</span> <span class="n">on</span> <span class="n">Jan</span> <span class="mi">13</span><span class="p">,</span> <span class="mi">2019</span><span class="p">)</span>
<span class="n">On</span> <span class="n">Jul</span> <span class="mi">26</span><span class="p">,</span> <span class="mi">2021</span> <span class="n">drop</span> <span class="n">support</span> <span class="k">for</span> <span class="n">NumPy</span> <span class="mf">1.17</span> <span class="p">(</span><span class="n">initially</span> <span class="n">released</span> <span class="n">on</span> <span class="n">Jul</span> <span class="mi">26</span><span class="p">,</span> <span class="mi">2019</span><span class="p">)</span>
<span class="n">On</span> <span class="n">Dec</span> <span class="mi">22</span><span class="p">,</span> <span class="mi">2021</span> <span class="n">drop</span> <span class="n">support</span> <span class="k">for</span> <span class="n">NumPy</span> <span class="mf">1.18</span> <span class="p">(</span><span class="n">initially</span> <span class="n">released</span> <span class="n">on</span> <span class="n">Dec</span> <span class="mi">22</span><span class="p">,</span> <span class="mi">2019</span><span class="p">)</span>
<span class="n">On</span> <span class="n">Dec</span> <span class="mi">26</span><span class="p">,</span> <span class="mi">2021</span> <span class="n">drop</span> <span class="n">support</span> <span class="k">for</span> <span class="n">Python</span> <span class="mf">3.7</span> <span class="p">(</span><span class="n">initially</span> <span class="n">released</span> <span class="n">on</span> <span class="n">Jun</span> <span class="mi">27</span><span class="p">,</span> <span class="mi">2018</span><span class="p">)</span>
<span class="n">On</span> <span class="n">Jun</span> <span class="mi">21</span><span class="p">,</span> <span class="mi">2022</span> <span class="n">drop</span> <span class="n">support</span> <span class="k">for</span> <span class="n">NumPy</span> <span class="mf">1.19</span> <span class="p">(</span><span class="n">initially</span> <span class="n">released</span> <span class="n">on</span> <span class="n">Jun</span> <span class="mi">20</span><span class="p">,</span> <span class="mi">2020</span><span class="p">)</span>
<span class="n">On</span> <span class="n">Jan</span> <span class="mi">31</span><span class="p">,</span> <span class="mi">2023</span> <span class="n">drop</span> <span class="n">support</span> <span class="k">for</span> <span class="n">NumPy</span> <span class="mf">1.20</span> <span class="p">(</span><span class="n">initially</span> <span class="n">released</span> <span class="n">on</span> <span class="n">Jan</span> <span class="mi">31</span><span class="p">,</span> <span class="mi">2021</span><span class="p">)</span>
<span class="n">On</span> <span class="n">Apr</span> <span class="mi">14</span><span class="p">,</span> <span class="mi">2023</span> <span class="n">drop</span> <span class="n">support</span> <span class="k">for</span> <span class="n">Python</span> <span class="mf">3.8</span> <span class="p">(</span><span class="n">initially</span> <span class="n">released</span> <span class="n">on</span> <span class="n">Oct</span> <span class="mi">14</span><span class="p">,</span> <span class="mi">2019</span><span class="p">)</span>
<span class="n">On</span> <span class="n">Jun</span> <span class="mi">23</span><span class="p">,</span> <span class="mi">2023</span> <span class="n">drop</span> <span class="n">support</span> <span class="k">for</span> <span class="n">NumPy</span> <span class="mf">1.21</span> <span class="p">(</span><span class="n">initially</span> <span class="n">released</span> <span class="n">on</span> <span class="n">Jun</span> <span class="mi">22</span><span class="p">,</span> <span class="mi">2021</span><span class="p">)</span>
<span class="n">On</span> <span class="n">Jan</span> <span class="mi">01</span><span class="p">,</span> <span class="mi">2024</span> <span class="n">drop</span> <span class="n">support</span> <span class="k">for</span> <span class="n">NumPy</span> <span class="mf">1.22</span> <span class="p">(</span><span class="n">initially</span> <span class="n">released</span> <span class="n">on</span> <span class="n">Dec</span> <span class="mi">31</span><span class="p">,</span> <span class="mi">2021</span><span class="p">)</span>
<span class="n">On</span> <span class="n">Apr</span> <span class="mi">05</span><span class="p">,</span> <span class="mi">2024</span> <span class="n">drop</span> <span class="n">support</span> <span class="k">for</span> <span class="n">Python</span> <span class="mf">3.9</span> <span class="p">(</span><span class="n">initially</span> <span class="n">released</span> <span class="n">on</span> <span class="n">Oct</span> <span class="mi">05</span><span class="p">,</span> <span class="mi">2020</span><span class="p">)</span>
<span class="n">On</span> <span class="n">Jun</span> <span class="mi">22</span><span class="p">,</span> <span class="mi">2024</span> <span class="n">drop</span> <span class="n">support</span> <span class="k">for</span> <span class="n">NumPy</span> <span class="mf">1.23</span> <span class="p">(</span><span class="n">initially</span> <span class="n">released</span> <span class="n">on</span> <span class="n">Jun</span> <span class="mi">22</span><span class="p">,</span> <span class="mi">2022</span><span class="p">)</span>
<span class="n">On</span> <span class="n">Dec</span> <span class="mi">18</span><span class="p">,</span> <span class="mi">2024</span> <span class="n">drop</span> <span class="n">support</span> <span class="k">for</span> <span class="n">NumPy</span> <span class="mf">1.24</span> <span class="p">(</span><span class="n">initially</span> <span class="n">released</span> <span class="n">on</span> <span class="n">Dec</span> <span class="mi">18</span><span class="p">,</span> <span class="mi">2022</span><span class="p">)</span>
<span class="n">On</span> <span class="n">Apr</span> <span class="mi">04</span><span class="p">,</span> <span class="mi">2025</span> <span class="n">drop</span> <span class="n">support</span> <span class="k">for</span> <span class="n">Python</span> <span class="mf">3.10</span> <span class="p">(</span><span class="n">initially</span> <span class="n">released</span> <span class="n">on</span> <span class="n">Oct</span> <span class="mi">04</span><span class="p">,</span> <span class="mi">2021</span><span class="p">)</span>
<span class="n">On</span> <span class="n">Apr</span> <span class="mi">24</span><span class="p">,</span> <span class="mi">2026</span> <span class="n">drop</span> <span class="n">support</span> <span class="k">for</span> <span class="n">Python</span> <span class="mf">3.11</span> <span class="p">(</span><span class="n">initially</span> <span class="n">released</span> <span class="n">on</span> <span class="n">Oct</span> <span class="mi">24</span><span class="p">,</span> <span class="mi">2022</span><span class="p">)</span>
</pre></div>
</div>
</section>
</section>
<section id="implementation">
<h2>Implementation<a class="headerlink" href="#implementation" title="Link to this heading">#</a></h2>
<p>We suggest that all projects adopt the following language into their
development guidelines:</p>
<blockquote>
<div><p>This project supports:</p>
<ul class="simple">
<li><p>All minor versions of Python released 42 months prior to the
project, and at minimum the two latest minor versions.</p></li>
<li><p>All minor versions of <code class="docutils literal notranslate"><span class="pre">numpy</span></code> released in the 24 months prior
to the project, and at minimum the last three minor versions.</p></li>
</ul>
<p>In <code class="docutils literal notranslate"><span class="pre">setup.py</span></code>, the <code class="docutils literal notranslate"><span class="pre">python_requires</span></code> variable should be set to
the minimum supported version of Python. All supported minor
versions of Python should be in the test matrix and have binary
artifacts built for the release.</p>
<p>Minimum Python and NumPy version support should be adjusted upward
on every major and minor release, but never on a patch release.</p>
</div></blockquote>
</section>
<section id="backward-compatibility">
<h2>Backward compatibility<a class="headerlink" href="#backward-compatibility" title="Link to this heading">#</a></h2>
<p>No backward compatibility issues.</p>
</section>
<section id="alternatives">
<h2>Alternatives<a class="headerlink" href="#alternatives" title="Link to this heading">#</a></h2>
<section id="ad-hoc-version-support">
<h3>Ad-Hoc version support<a class="headerlink" href="#ad-hoc-version-support" title="Link to this heading">#</a></h3>
<p>A project could, on every release, evaluate whether to increase
the minimum version of Python supported.
As a major downside, an ad-hoc approach makes it hard for downstream users to predict what
the future minimum versions will be. As there is no objective threshold
to when the minimum version should be dropped, it is easy for these
version support discussions to devolve into <a class="reference external" href="https://en.wikipedia.org/wiki/Wikipedia:Avoid_Parkinson%27s_bicycle-shed_effect">bike shedding</a> and acrimony.</p>
</section>
<section id="all-cpython-supported-versions">
<h3>All CPython supported versions<a class="headerlink" href="#all-cpython-supported-versions" title="Link to this heading">#</a></h3>
<p>The CPython supported versions of Python are listed in the Python
Developers Guide and the Python PEPs. Supporting these is a very clear
and conservative approach. However, it means that there exists a four
year lag between when a new features is introduced into the language
and when a project is able to use it. Additionally, for projects with
compiled extensions this requires building many binary artifacts for
each release.</p>
<p>For the case of NumPy, many projects carry workarounds to bugs that
are fixed in subsequent versions of NumPy. Being proactive about
increasing the minimum version of NumPy allows downstream
packages to carry fewer version-specific patches.</p>
</section>
<section id="default-version-on-linux-distribution">
<h3>Default version on Linux distribution<a class="headerlink" href="#default-version-on-linux-distribution" title="Link to this heading">#</a></h3>
<p>The policy could be to support the version of Python that ships by
default in the latest Ubuntu LTS or CentOS/RHEL release. However, we
would still have to standardize across the community which
distribution to follow.</p>
<p>By following the versions supported by major Linux distributions, we
are giving up technical control of our projects to external
organizations that may have different motivations and concerns than we
do.</p>
</section>
<section id="n-minor-versions-of-python">
<h3>N minor versions of Python<a class="headerlink" href="#n-minor-versions-of-python" title="Link to this heading">#</a></h3>
<p>Given the current release cadence of the Python, the proposed time (42
months) is roughly equivalent to “the last two” Python minor versions.
However, if Python changes their release cadence substantially, any
rule based solely on the number of minor releases may need to be
changed to remain sensible.</p>
<p>A more fundamental problem with a policy based on number of Python
releases is that it is hard to predict when support for a given minor
version of Python will be dropped as that requires correctly
predicting the release schedule of Python for the next 3-4 years. A
time-based rule, in contrast, only depends on past events
and the length of the support window.</p>
</section>
<section id="time-window-from-the-x-y-1-python-release">
<h3>Time window from the X.Y.1 Python release<a class="headerlink" href="#time-window-from-the-x-y-1-python-release" title="Link to this heading">#</a></h3>
<p>This is equivalent to a few month longer support window from the X.Y.0
release. This is because X.Y.1 bug-fix release is typically a few
months after the X.Y.0 release, thus a N month window from X.Y.1 is
roughly equivalent to a N+3 month from X.Y.0.</p>
<p>The X.Y.0 release is naturally a special release. If we were to
anchor the window on X.Y.1 we would then have the discussion of why
not X.Y.M?</p>
</section>
</section>
<section id="discussion">
<h2>Discussion<a class="headerlink" href="#discussion" title="Link to this heading">#</a></h2>
</section>
<section id="references-and-footnotes">
<h2>References and footnotes<a class="headerlink" href="#references-and-footnotes" title="Link to this heading">#</a></h2>
<p>Code to generate support and drop schedule tables</p>
<div class="highlight-default notranslate"><div class="highlight"><pre><span></span><span class="kn">from</span> <span class="nn">datetime</span> <span class="kn">import</span> <span class="n">datetime</span><span class="p">,</span> <span class="n">timedelta</span>
<span class="n">data</span> <span class="o">=</span> <span class="s2">"""Jan 15, 2017: NumPy 1.12</span>
<span class="s2">Sep 13, 2015: Python 3.5</span>
<span class="s2">Dec 23, 2016: Python 3.6</span>
<span class="s2">Jun 27, 2018: Python 3.7</span>
<span class="s2">Jun 07, 2017: NumPy 1.13</span>
<span class="s2">Jan 06, 2018: NumPy 1.14</span>
<span class="s2">Jul 23, 2018: NumPy 1.15</span>
<span class="s2">Jan 13, 2019: NumPy 1.16</span>
<span class="s2">Jul 26, 2019: NumPy 1.17</span>
<span class="s2">Oct 14, 2019: Python 3.8</span>
<span class="s2">Dec 22, 2019: NumPy 1.18</span>
<span class="s2">Jun 20, 2020: NumPy 1.19</span>
<span class="s2">Oct 05, 2020: Python 3.9</span>
<span class="s2">Jan 30, 2021: NumPy 1.20</span>
<span class="s2">Jun 22, 2021: NumPy 1.21</span>
<span class="s2">Oct 04, 2021: Python 3.10</span>
<span class="s2">Dec 31, 2021: NumPy 1.22</span>
<span class="s2">Jun 22, 2022: NumPy 1.23</span>
<span class="s2">Oct 24, 2022: Python 3.11</span>
<span class="s2">Dec 18, 2022: NumPy 1.24</span>
<span class="s2">"""</span>
<span class="n">releases</span> <span class="o">=</span> <span class="p">[]</span>
<span class="n">plus42</span> <span class="o">=</span> <span class="n">timedelta</span><span class="p">(</span><span class="n">days</span><span class="o">=</span><span class="nb">int</span><span class="p">(</span><span class="mi">365</span><span class="o">*</span><span class="mf">3.5</span> <span class="o">+</span> <span class="mi">1</span><span class="p">))</span>
<span class="n">plus24</span> <span class="o">=</span> <span class="n">timedelta</span><span class="p">(</span><span class="n">days</span><span class="o">=</span><span class="nb">int</span><span class="p">(</span><span class="mi">365</span><span class="o">*</span><span class="mi">2</span> <span class="o">+</span> <span class="mi">1</span><span class="p">))</span>
<span class="k">for</span> <span class="n">line</span> <span class="ow">in</span> <span class="n">data</span><span class="o">.</span><span class="n">splitlines</span><span class="p">():</span>
<span class="n">date</span><span class="p">,</span> <span class="n">project_version</span> <span class="o">=</span> <span class="n">line</span><span class="o">.</span><span class="n">split</span><span class="p">(</span><span class="s1">':'</span><span class="p">)</span>
<span class="n">project</span><span class="p">,</span> <span class="n">version</span> <span class="o">=</span> <span class="n">project_version</span><span class="o">.</span><span class="n">strip</span><span class="p">()</span><span class="o">.</span><span class="n">split</span><span class="p">(</span><span class="s1">' '</span><span class="p">)</span>
<span class="n">release</span> <span class="o">=</span> <span class="n">datetime</span><span class="o">.</span><span class="n">strptime</span><span class="p">(</span><span class="n">date</span><span class="p">,</span> <span class="s1">'%b </span><span class="si">%d</span><span class="s1">, %Y'</span><span class="p">)</span>
<span class="k">if</span> <span class="n">project</span><span class="o">.</span><span class="n">lower</span><span class="p">()</span> <span class="o">==</span> <span class="s1">'numpy'</span><span class="p">:</span>
<span class="n">drop</span> <span class="o">=</span> <span class="n">release</span> <span class="o">+</span> <span class="n">plus24</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">drop</span> <span class="o">=</span> <span class="n">release</span> <span class="o">+</span> <span class="n">plus42</span>
<span class="n">releases</span><span class="o">.</span><span class="n">append</span><span class="p">((</span><span class="n">drop</span><span class="p">,</span> <span class="n">project</span><span class="p">,</span> <span class="n">version</span><span class="p">,</span> <span class="n">release</span><span class="p">))</span>
<span class="n">releases</span> <span class="o">=</span> <span class="nb">sorted</span><span class="p">(</span><span class="n">releases</span><span class="p">,</span> <span class="n">key</span><span class="o">=</span><span class="k">lambda</span> <span class="n">x</span><span class="p">:</span> <span class="n">x</span><span class="p">[</span><span class="mi">0</span><span class="p">])</span>
<span class="n">py_major</span><span class="p">,</span><span class="n">py_minor</span> <span class="o">=</span> <span class="nb">sorted</span><span class="p">([</span><span class="nb">int</span><span class="p">(</span><span class="n">x</span><span class="p">)</span> <span class="k">for</span> <span class="n">x</span> <span class="ow">in</span> <span class="n">r</span><span class="p">[</span><span class="mi">2</span><span class="p">]</span><span class="o">.</span><span class="n">split</span><span class="p">(</span><span class="s1">'.'</span><span class="p">)]</span> <span class="k">for</span> <span class="n">r</span> <span class="ow">in</span> <span class="n">releases</span> <span class="k">if</span> <span class="n">r</span><span class="p">[</span><span class="mi">1</span><span class="p">]</span> <span class="o">==</span> <span class="s1">'Python'</span><span class="p">)[</span><span class="o">-</span><span class="mi">1</span><span class="p">]</span>
<span class="n">minpy</span> <span class="o">=</span> <span class="sa">f</span><span class="s2">"</span><span class="si">{</span><span class="n">py_major</span><span class="si">}</span><span class="s2">.</span><span class="si">{</span><span class="n">py_minor</span><span class="o">+</span><span class="mi">1</span><span class="si">}</span><span class="s2">+"</span>
<span class="n">num_major</span><span class="p">,</span><span class="n">num_minor</span> <span class="o">=</span> <span class="nb">sorted</span><span class="p">([</span><span class="nb">int</span><span class="p">(</span><span class="n">x</span><span class="p">)</span> <span class="k">for</span> <span class="n">x</span> <span class="ow">in</span> <span class="n">r</span><span class="p">[</span><span class="mi">2</span><span class="p">]</span><span class="o">.</span><span class="n">split</span><span class="p">(</span><span class="s1">'.'</span><span class="p">)]</span> <span class="k">for</span> <span class="n">r</span> <span class="ow">in</span> <span class="n">releases</span> <span class="k">if</span> <span class="n">r</span><span class="p">[</span><span class="mi">1</span><span class="p">]</span> <span class="o">==</span> <span class="s1">'NumPy'</span><span class="p">)[</span><span class="o">-</span><span class="mi">1</span><span class="p">]</span>
<span class="n">minnum</span> <span class="o">=</span> <span class="sa">f</span><span class="s2">"</span><span class="si">{</span><span class="n">num_major</span><span class="si">}</span><span class="s2">.</span><span class="si">{</span><span class="n">num_minor</span><span class="o">+</span><span class="mi">1</span><span class="si">}</span><span class="s2">+"</span>
<span class="n">toprint_drop_dates</span> <span class="o">=</span> <span class="p">[</span><span class="s1">''</span><span class="p">]</span>
<span class="n">toprint_support_table</span> <span class="o">=</span> <span class="p">[]</span>
<span class="k">for</span> <span class="n">d</span><span class="p">,</span> <span class="n">p</span><span class="p">,</span> <span class="n">v</span><span class="p">,</span> <span class="n">r</span> <span class="ow">in</span> <span class="n">releases</span><span class="p">[::</span><span class="o">-</span><span class="mi">1</span><span class="p">]:</span>
<span class="n">df</span> <span class="o">=</span> <span class="n">d</span><span class="o">.</span><span class="n">strftime</span><span class="p">(</span><span class="s1">'%b </span><span class="si">%d</span><span class="s1">, %Y'</span><span class="p">)</span>
<span class="n">toprint_drop_dates</span><span class="o">.</span><span class="n">append</span><span class="p">(</span>
<span class="sa">f</span><span class="s1">'On </span><span class="si">{</span><span class="n">df</span><span class="si">}</span><span class="s1"> drop support for </span><span class="si">{</span><span class="n">p</span><span class="si">}</span><span class="s1"> </span><span class="si">{</span><span class="n">v</span><span class="si">}</span><span class="s1"> '</span>
<span class="sa">f</span><span class="s1">'(initially released on </span><span class="si">{</span><span class="n">r</span><span class="o">.</span><span class="n">strftime</span><span class="p">(</span><span class="s2">"%b </span><span class="si">%d</span><span class="s2">, %Y"</span><span class="p">)</span><span class="si">}</span><span class="s1">)'</span><span class="p">)</span>
<span class="n">toprint_support_table</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="sa">f</span><span class="s1">'</span><span class="si">{</span><span class="n">df</span><span class="si">}</span><span class="s1"> </span><span class="si">{</span><span class="n">minpy</span><span class="si">:</span><span class="s1"><6</span><span class="si">}</span><span class="s1"> </span><span class="si">{</span><span class="n">minnum</span><span class="si">:</span><span class="s1"><5</span><span class="si">}</span><span class="s1">'</span><span class="p">)</span>
<span class="k">if</span> <span class="n">p</span><span class="o">.</span><span class="n">lower</span><span class="p">()</span> <span class="o">==</span> <span class="s1">'numpy'</span><span class="p">:</span>
<span class="n">minnum</span> <span class="o">=</span> <span class="n">v</span><span class="o">+</span><span class="s1">'+'</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">minpy</span> <span class="o">=</span> <span class="n">v</span><span class="o">+</span><span class="s1">'+'</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">"On next release, drop support for Python 3.5 (initially released on Sep 13, 2015)"</span><span class="p">)</span>
<span class="k">for</span> <span class="n">e</span> <span class="ow">in</span> <span class="n">toprint_drop_dates</span><span class="p">[</span><span class="o">-</span><span class="mi">4</span><span class="p">::</span><span class="o">-</span><span class="mi">1</span><span class="p">]:</span>
<span class="nb">print</span><span class="p">(</span><span class="n">e</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="s1">'============ ====== ====='</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="s1">'Date Python NumPy'</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="s1">'------------ ------ -----'</span><span class="p">)</span>
<span class="k">for</span> <span class="n">e</span> <span class="ow">in</span> <span class="n">toprint_support_table</span><span class="p">[</span><span class="o">-</span><span class="mi">4</span><span class="p">::</span><span class="o">-</span><span class="mi">1</span><span class="p">]:</span>
<span class="nb">print</span><span class="p">(</span><span class="n">e</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="s1">'============ ====== ====='</span><span class="p">)</span>
</pre></div>
</div>
</section>
<section id="copyright">
<h2>Copyright<a class="headerlink" href="#copyright" title="Link to this heading">#</a></h2>
<p>This document has been placed in the public domain.</p>
</section>
</section>
</article>
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<li class="toc-h2 nav-item toc-entry"><a class="reference internal nav-link" href="#abstract">Abstract</a></li>
<li class="toc-h2 nav-item toc-entry"><a class="reference internal nav-link" href="#detailed-description">Detailed description</a><ul class="nav section-nav flex-column">
<li class="toc-h3 nav-item toc-entry"><a class="reference internal nav-link" href="#support-table">Support Table</a></li>
<li class="toc-h3 nav-item toc-entry"><a class="reference internal nav-link" href="#drop-schedule">Drop Schedule</a></li>
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<li class="toc-h2 nav-item toc-entry"><a class="reference internal nav-link" href="#implementation">Implementation</a></li>
<li class="toc-h2 nav-item toc-entry"><a class="reference internal nav-link" href="#backward-compatibility">Backward compatibility</a></li>
<li class="toc-h2 nav-item toc-entry"><a class="reference internal nav-link" href="#alternatives">Alternatives</a><ul class="nav section-nav flex-column">
<li class="toc-h3 nav-item toc-entry"><a class="reference internal nav-link" href="#ad-hoc-version-support">Ad-Hoc version support</a></li>
<li class="toc-h3 nav-item toc-entry"><a class="reference internal nav-link" href="#all-cpython-supported-versions">All CPython supported versions</a></li>
<li class="toc-h3 nav-item toc-entry"><a class="reference internal nav-link" href="#default-version-on-linux-distribution">Default version on Linux distribution</a></li>
<li class="toc-h3 nav-item toc-entry"><a class="reference internal nav-link" href="#n-minor-versions-of-python">N minor versions of Python</a></li>
<li class="toc-h3 nav-item toc-entry"><a class="reference internal nav-link" href="#time-window-from-the-x-y-1-python-release">Time window from the X.Y.1 Python release</a></li>
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<li class="toc-h2 nav-item toc-entry"><a class="reference internal nav-link" href="#discussion">Discussion</a></li>
<li class="toc-h2 nav-item toc-entry"><a class="reference internal nav-link" href="#references-and-footnotes">References and footnotes</a></li>
<li class="toc-h2 nav-item toc-entry"><a class="reference internal nav-link" href="#copyright">Copyright</a></li>
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