JonasBang wrote:I expect that I should delete the child and only keep the parent now, right?
YES.
If that does not help with the issue, rename the templates plugin_staticpage.tpl file to _plugin_staticpage.tpl. This would force the fallback to use the plugins directory tpl file(s).
Deleted the child dir made functionality worse, but it did report the correct version. Moving the new 4.0.7 dir down to a child dir fixed it. Now it reports the correct version, and the static pages works
My install seems to be somewhat fucked, or what is your opinion? I would be tempted to make a fresh install ...