Thank you very much. It now tells me that I have upgraded to zc.buildout-2.13.2 but it is still giving me an error:
$ sudo pip install --upgrade zc.buildout
DEPRECATION: Python 2.7 will reach the end of its life on January 1st, 2020. Please upgrade your Python as Python 2.7 won't be maintained after that date. A future version of pip will drop support for Python 2.7. More details about Python 2 support in pip, can be found at Release process - pip documentation v24.0.dev0
WARNING: The directory '/home/user/.cache/pip/http' or its parent directory is not owned by the current user and the cache has been disabled. Please check the permissions and owner of that directory. If executing pip with sudo, you may want sudo's -H flag.
WARNING: The directory '/home/user/.cache/pip' or its parent directory is not owned by the current user and caching wheels has been disabled. check the permissions and owner of that directory. If executing pip with sudo, you may want sudo's -H flag.
Processing /home/user/.cache/pip/wheels/c7/91/e5/cee51af09e8fbea27100c93aff9a6a267227234625043b3c4f/zc.buildout-2.13.2-py2.py3-none-any.whl
Requirement already satisfied, skipping upgrade: setuptools>=8.0 in /home/user/.local/lib/python2.7/site-packages (from zc.buildout) (42.0.2)
Installing collected packages: zc.buildout
Found existing installation: zc.buildout 2.12.0
Uninstalling zc.buildout-2.12.0:
Successfully uninstalled zc.buildout-2.12.0
Successfully installed zc.buildout-2.13.2$ sudo -u plone bin/buildout
Version and requirements information containing zc.buildout:
Requirement of plone.recipe.zeoserver==2.0.1: zc.buildout
Requirement of zc.recipe.egg: zc.buildout>=2.12.0
Requirement of zc.buildout: setuptools>=8.0
While:
Installing.
Getting section zeoserver.
Initializing section zeoserver.
Installing recipe plone.recipe.zeoserver.
> Error: There is a version conflict.
> We already have: zc.buildout 2.5.3
> but zc.recipe.egg 2.0.7 requires 'zc.buildout>=2.12.0'.