Regarding filebase, are uploads stored separately from Woltlab attachments? I wonder if it is compatiable with the CDN connection for attachments plugin.
And is it possible to use multilanguage on entries? Online demo doesn't have this feature.
Yes, it is stored differently and does not support CDNs. One entry can be assigned to a language and is only visible to users that speak this language. However it does not support multi-language items.