Just tested it and the new version works. The large event with 1872 attendees is now imported.
Is is so large that the calendar app takes several seconds to load it.
No peer certificate error even when selecting http
I get “E/A-Fehler: No peer certificate” even when selecting “http” (not “https”) for my server (ask me for an url).
It has a self-signed certificate, but should work with http.
Can you please send the URL to email@example.com? I have use http:// to test with HTTP only servers and I didn’t experience this problem.
You have a mail.
OwnCloud seems to redirect to https:// by default (or at least in your installation). So I will close this issue as a duplicate of issue #3.