Plone 5.2.3: I think my zinstance python 2.7 version is now out of sync with my Linux distribution's python 2.7. How do I fix it?

Hello, I recently upgraded by Debian version to Buster from Squeeze. Now my previously working Plone v5.2.3 instance will not run. How do I update my zinstance/bin/python2.7 so it is compatible with the one in Debian Buster? If it were a proper python virtualenv, I think I would know what to do, maybe it is, and I can use easy_install or pip to update it?

Below is my /bin/buildout output:

eric@bambu:~/Plone5/zinstance/bin$ ./buildout > /home/eric/error.txt
Traceback (most recent call last):
File "./buildout", line 5, in
from zc.buildout.buildout import main
File "/home/eric/Plone5/zinstance/local/lib/python2.7/site-packages/zc/buildout/buildout.py", line 17, in
from zc.buildout.rmtree import rmtree
File "/home/eric/Plone5/zinstance/local/lib/python2.7/site-packages/zc/buildout/rmtree.py", line 18, in
import doctest
File "/usr/lib/python2.7/doctest.py", line 99, in
import unittest, difflib, pdb, tempfile
File "/usr/lib/python2.7/unittest/init.py", line 64, in
from .main import TestProgram, main
File "/usr/lib/python2.7/unittest/main.py", line 7, in
from . import loader, runner
File "/usr/lib/python2.7/unittest/runner.py", line 7, in
from .signals import registerResult
File "/usr/lib/python2.7/unittest/signals.py", line 2, in
import weakref
File "/usr/lib/python2.7/weakref.py", line 14, in
from _weakref import (
ImportError: cannot import name _remove_dead_weakref

Here is my ./zinstance/bin directory (notice how old the python 2.7 is 2016!), and my new Debian Buster python 2.7 is recent (which is probably what's causing the mismatch):

eric@bambu:~/Plone5/zinstance/bin$ ls -al
total 3832
drwxr-xr-x 2 eric eric 4096 Mar 17 19:44 .
drwxr-xr-x 13 eric eric 4096 Mar 17 19:22 ..
-rwxr-xr-- 1 eric eric 2238 Jan 22 2016 activate
-rwxr-xr-- 1 eric eric 1264 Jan 22 2016 activate.csh
-rwxr-xr-- 1 eric eric 2477 Jan 22 2016 activate.fish
-rwxr-xr-- 1 eric eric 1137 Jan 22 2016 activate_this.py
-rwxr-xr-- 1 eric eric 2467 Dec 14 21:03 backup
-rwxr-xr-- 1 eric eric 244 Dec 2 05:14 buildout
-rwxr-xr-- 1 eric eric 255 Dec 2 05:13 easy_install
-rwxr-xr-- 1 eric eric 255 Dec 2 05:13 easy_install-2.7
-rwxr-xr-- 1 eric eric 20351 Jan 4 17:46 instance
-rwxr-xr-- 1 eric eric 249 Dec 2 05:12 pip
-rwxr-xr-- 1 eric eric 249 Dec 2 05:12 pip2
-rwxr-xr-- 1 eric eric 249 Dec 2 05:12 pip2.7
-rwxr-xr-- 1 eric eric 619 Dec 14 21:09 plonectl
lrwxrwxrwx 1 eric eric 9 Dec 21 19:04 python -> python2.7
lrwxrwxrwx 1 eric eric 9 Dec 21 19:04 python2 -> python2.7
-rwxr-xr-- 1 eric eric 3785928 Jan 22 2016 python2.7
-rwxr-xr-- 1 eric eric 1613 Dec 14 21:03 repozo
-rwxr-xr-- 1 eric eric 2468 Dec 14 21:03 restore
-rwxr-xr-- 1 eric eric 2469 Dec 14 21:03 snapshotbackup
-rwxr-xr-- 1 eric eric 2477 Dec 14 21:03 snapshotrestore
-rwxr-xr-- 1 eric eric 233 Dec 2 05:13 wheel
-rwxr-xr-- 1 eric eric 2131 Dec 14 21:03 zeopack
-rwxr-xr-- 1 eric eric 3275 Dec 14 21:03 zeoserver
-rwxr-xr-- 1 eric eric 20550 Dec 14 23:08 zopepy
eric@bambu:~/Plone5/zinstance/bin$

I was able to get past this issue by replace my zinstance/bin/python2.7 dating back to 2016, with a new version of the same file I got from the new 5.2.4 unified installer at https://launchpad.net/plone/5.2/5.2.4/+download/Plone-5.2.4-UnifiedInstaller-1.0.tgz . Buildout ran successfully after that. Still not sure what the automated was to update this would be. It will be nice when buildout is gone, and it's all pip.

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