I am still having problems installing PloneHotfix202101518. I was able to upgrade to Plone 4.3.20 but that did not help with installing PloneHotfix20210518. Here are some more details about my system. I am running Zope 2.13.30 and Python 2.7.16.
My site is simple. It was probably first stood up in 2005 or so by a great old friend of mine who is no longer available to help with plone. By going to http://testing.mysite.org/prefs_install_products_form I see that there are only three active add-ons. The currently active add-ons are “HTTP caching support 1.1.12”, “Plone Classic Theme 1.5.1”, and “Workflow Policy Support (CMFPlacefulWorkflow) 1.5.15”. I tried adding plone.app.caching = 2.1.0 to the [versions] section of buildout.cfg and running buildout to try and update it to the most recent version (Upgrade add-on products — Plone Documentation v5.2). This generated the same error message
Error: Couldn't find a distribution for 'plone.app.caching==2.1.0'.
I have been reading Plone Upgrade Guide — Plone Documentation v5.2 . I suspect that if I upgrade to Plone 5.2 this will fix my problems. Unfortunately, I have not found where that documentation tells how to upgrade from 4.x to 5.2. The Upgrading Plone 4.x To 5.0 — Plone Documentation v5.2 document appears to have lots of cautions, guidance and such but I am not finding where on that page or any of the others where it describes what I need to change to implement the upgrade. Do simply replace the occurrences of 4.3.20 in buildout.cfg with 5.2.3 and run buildout? Where can I find a guide or documentation that will help me with this? I searched on Google for more help with Plone migration without success. I think I am missing a basic concept or something.
I would appreciate any help you can give me on this. Thanks, Michael