adjust some wording for the removal of Python 2.x compatibility

doc/src/Build_extras.rst

@@ -1139,11 +1139,10 @@ POEMS package
 PYTHON package
 ---------------------------
 
-Building with the PYTHON package requires you have a the Python development
+Building with the PYTHON package requires you have a the Python
-headers and library available on your system, which needs to be a Python 2.7
+development headers and library available on your system, which
-version or a Python 3.x version.  Since support for Python 2.x has ended,
+needs to be Python version 3.6 or later.  See ``lib/python/README``
-using Python 3.x is strongly recommended. See ``lib/python/README`` for
+for additional details.
-additional details.
 
 .. tabs::
 
@@ -1159,7 +1158,7 @@ additional details.
       set the Python_EXECUTABLE variable to specify which Python
       interpreter should be used.  Note note that you will also need to
       have the development headers installed for this version,
-      e.g. python2-devel.
+      e.g. python3-devel.
 
    .. tab:: Traditional make
 

doc/src/Build_make.rst

@@ -30,9 +30,9 @@ additional tools to be available and functioning.
   * A Bourne shell compatible "Unix" shell program (frequently this is ``bash``)
   * A few shell utilities: ``ls``, ``mv``, ``ln``, ``rm``, ``grep``, ``sed``, ``tr``, ``cat``, ``touch``, ``diff``, ``dirname``
   * Python (optional, required for ``make lib-<pkg>`` in the ``src``
-    folder).  Python scripts are currently tested with python 2.7 and
+    folder).  Python scripts are currently tested with 3.6 to 3.11.
-    3.6 to 3.11. The procedure for :doc:`building the documentation
+    The procedure for :doc:`building the documentation <Build_manual>`
-    <Build_manual>` *requires* Python 3.5 or later.
+    *requires* Python 3.8 or later.
 
 Getting started
 ^^^^^^^^^^^^^^^

doc/src/Intro_portability.rst

@@ -13,10 +13,14 @@ Programming language standards
 
 Most of the C++ code currently requires a compiler compatible with the
 C++11 standard, the KOKKOS package currently requires C++17.  Most of
-the Python code is written to be compatible with Python 3.5 or later or
+the Python code is written to be compatible with Python 3.6 or later.
-Python 2.7.  Some Python scripts *require* Python 3 and a few others
-still need to be ported from Python 2 to Python 3.
 
+.. deprecated:: TBD
+
+Python 2.x is no longer supported and trying to use it, e.g. for the
+LAMMPS Python module should result in an error.  If you come across
+some part of the LAMMPS distribution that is not (yet) compatible with
+Python 3, please notify the LAMMPS developers.
 
 Build systems
 ^^^^^^^^^^^^^
@@ -24,8 +28,8 @@ Build systems
 LAMMPS can be compiled from source code using a (traditional) build
 system based on shell scripts, a few shell utilities (grep, sed, cat,
 tr) and the GNU make program. This requires running within a Bourne
-shell (``/bin/sh``).  Alternatively, a build system with different back ends
+shell (``/bin/sh``).  Alternatively, a build system with different back
-can be created using CMake.  CMake must be at least version 3.16.
+ends can be created using CMake.  CMake must be at least version 3.16.
 
 Operating systems
 ^^^^^^^^^^^^^^^^^

doc/src/Modify_requirements.rst

@@ -189,10 +189,8 @@ of the contribution.  As of January 2023, all previously included
 Fortran code for the LAMMPS executable has been replaced by equivalent
 C++ code.
 
-Python code must be compatible with Python 3.5 and later.  Large parts
+Python code currently must be compatible with Python 3.6.  If a later
-of LAMMPS (including the :ref:`PYTHON package <PKG-PYTHON>`) are also
+version or Python is required, it needs to be documented.
-compatible with Python 2.7.  Compatibility with Python 2.7 is desirable,
-but compatibility with Python 3.5 is **required**.
 
 Compatibility with older programming language standards is very
 important to maintain portability and availability of LAMMPS on many

doc/src/Packages_details.rst

@@ -2428,7 +2428,7 @@ ways to use LAMMPS and Python together.
 
    Building with the PYTHON package assumes you have a Python development
    environment (headers and libraries) available on your system, which needs
-   to be either Python version 2.7 or Python 3.5 and later.
+   to be Python version 3.6 or later.
 
 **Install:**
 

doc/src/Python_overview.rst

@@ -44,15 +44,11 @@ Below is an example output for Python version 3.8.5.
 .. warning::
 
    The options described in this section of the manual for using Python
-   with LAMMPS currently support either Python 2 or 3.  Specifically
+   with LAMMPS support only Python 3.6 or later.  For use with Python
-   version 2.7 or later and 3.6 or later.  Since the Python community no
+   2.x you will need to use an older LAMMPS version like 29 Aug 2024
-   longer maintains Python 2 (see `this notice
+   or older.  If you notice Python code in the LAMMPS distribution that
-   <https://www.python.org/doc/sunset-python-2/>`_), we recommend use of
+   is not compatible with Python 3, please contact the LAMMPS developers
-   Python 3 with LAMMPS.  While Python 2 code should continue to work,
+   or submit `and issue on GitHub <https://github.com/lammps/lammps/issues>`_
-   that is not something we can guarantee long-term.  If you notice
-   Python code in the LAMMPS distribution that is not compatible with
-   Python 3, please contact the LAMMPS developers or submit `and issue
-   on GitHub <https://github.com/lammps/lammps/issues>`_
 
 ---------