Plone 5.2 should follow up with Zope 4 releases. (currently we are on Zope 4.1.3).
First, in Zope 4.2 WebDAV was reintroduced for ZServer. Probably this is for some of you good news....
Now we managed to make 4.2.1 work on Python 3, but with Archetypes on Python 2.7 it fails. See Pull Request here: https://github.com/plone/buildout.coredev/pull/644
Who with some insight knowledge in WebDAV and Archetypes can help here?
Next step is then to go further to Zope 4.3 - which enables WebDAV also for WSGI servers. Given we're fine on Zope 4.2.1 there should not be larger problems left - I hope.
There is also a problem left in Products.CMFQuickInstallerTool PR23 which needs some love.
For Plone 6 we want to have Zope 5 as base (which main difference is to be Python 3 only) - and a precondition is to have a Plone on Zope 4.3 without the Zope 5 deprecation warnings running (most of them were eliminated at Alpine City Sprint).