@herz_ag yes, thats possible with WebDAV I think. We’ve had a generalized WebDAV sync app in mind but right now we’re focusing on CalDAV/CardDAV (It is based on WebDAV but still very different). So it will not come in the near future Nevertheless the idea of such an app was in our minds for long time. So if not somebody else is making it maybe it will be a new app developed.
Log-term syncing with davdroid
I prefer to have all my calendar entries (last 10 years and more) on my mobile device. If I clear the day parameter for past entries in the davdroid settings it works and I get all my entries from owncloud after synchronizing. But if I change this parameter back to e.g. 90 days (for reducing sync time) my entries oder than 90 days disappear after syncing. Is this a wanted behaviour? Is there a possibility to keep the old entries (difference between long-term and normal sync)?
Yes, this is the wanted behaviour and no, there is no option for that.