I am looking for software to sync my Calendar and my Contacts between Thunderbird, my Android phones and probably other clients like KDEs Kalendar and Kontacts. I want to have both parts available offline (cached) at least for Thunderbird and for Android.
Google is out of question for obvious security and privacy reasons (can't be trusted).
Which Server software and which way could give me the most success? Does anyone have partial working solutions with some experience on the stability of the solution? How about the security aspect while syncing across unsecure networks (public hotspots for example)?
Tried so far: calendarserver (calendar works) radicale (calendar and adressbook work, but not for android, also lost my adressbook thanks to the sogo extension)