Kolejna perełka
DAVdroid
http://davdroid.bitfire.at/what-is-davdroid
DAVdroid is an open-source CalDAV/CardDAV synchronization app for Android 4+.
- two-way-synchronization (server client, server always wins)
- focused on simplicity, security and privacy
- native Android 4+ implementation
- lightweight application, not cluttered with "features"
- flawless integration with device and address book/calendar apps
- high-performance algorithms
- seperately usable (either CalDAV or CardDAV)
- free and open-source software (FOSS)