thank you, but adding unwicked as an egg gave the following error :
[...]
File "/opt/Plone-4.3.18/zinstance/src/unwicked/unwicked/init.py", line 1, in
from plone.app.upgrade.utils import alias_module
zope.configuration.xmlconfig.ZopeXMLConfigurationError: File "/opt/Plone-4.3.18/zinstance/parts/instance/etc/site.zcml", line 12.2-12.39
ZopeXMLConfigurationError: File "/opt/Plone-4.3.18/buildout-cache/eggs/Products.CMFPlone-4.3.20-py2.7.egg/Products/CMFPlone/meta.zcml", line 42.4-46.10
ImportError: No module named app.upgrade.utils
Why did you add plone.app.contenttypes to your Plone 4.3 site?
You don't need that:You can create a new Plone 5.2 instance with the last/latest python 2, put a copy of your Plone 4.3 content db in/under that install, run the upgrade steps and then run the atct_migrator
It is also in the Plone 5.2 install where you would add the unwicked add'on .