Additional data:
After reading the documentation of collective.simplewiki, I saw, that it is only supported in Plone 5.x - therefore I just made my buildout.cfg containing collective.simplewiki and upgrade to 5.0.7.
After that my Plone crashes when updating it and an error occurs, similar to the one I already had a topic here in the community-forum: Ugrade 4.3.15 -> 5.0.7 seems ok but cannot upgrade site within browser
-> @pbauer: You suggested then to add wicked to the buildout 
Somehow I'm turning myself in a circle 
I would be glad to finally migrate my 4.3-Plone properly to 5, but somehow whatever I try does not work. I Would very much appreciate finding somebody willing to properly help me through the whole process...
I am quite lost and have no clue of how to continue with our Intranet...
Appreciate any help and kind regards
David
PS: The error I see when I want to do Upgrade unter Plone 5.0.7 os the following:
Site Error
An error was encountered while publishing this resource.
Sorry, a site error occurred.
Traceback (innermost last):
Module ZPublisher.Publish, line 249, in publish_module_standard
Module ZPublisher.Publish, line 197, in publish
Module zope.event, line 31, in notify
Module zope.component.event, line 24, in dispatch
Module zope.component._api, line 136, in subscribers
Module zope.component.registry, line 321, in subscribers
Module ZODB.Connection, line 860, in setstate
Module ZODB.Connection, line 914, in _setstate
Module ZODB.serialize, line 613, in setGhostState
Module zope.component.persistentregistry, line 40, in __setstate__
Module zope.interface.adapter, line 91, in _createLookup
Module zope.interface.adapter, line 439, in __init__
Module zope.interface.adapter, line 476, in init_extendors
Module zope.interface.adapter, line 480, in add_extendor
AttributeError: type object 'IFieldValueSetter' has no attribute '__iro__'
Troubleshooting Suggestions
The URL may be incorrect.
The parameters passed to this resource may be incorrect.
A resource that this resource relies on may be encountering an error.
For more detailed information about the error, please refer to the error log.
If the error persists please contact the site maintainer. Thank you for your patience.
Afterwards I have again to restart the Plone-service on LINUX in order to be able to go again to the URL to upgrade the Plone-site...