To try the thousands of add-ons available here, download Mozilla Firefox, a fast, free way to surf the Web!
CloseWelcome to Firefox Add-ons.
Choose from thousands of extra features and styles to make Firefox your own.
CloseReview for ThunderSync by Sven Giermann
Rated 4 out of 5 stars
I can confirm what Reiner told on April 14, 2015:
https://addons.mozilla.org/de/thunderbird/addon/thundersync/reviews/699270/
I tried to import from UTF-8 VCF file, but all umlauts got worse. Simple workaround for me: copy all files into a single VCF, convert this to ISO-8859-1 and import from this single file --> worked.
But it's not the right way to simply workaround existing UTF-8 coded files...
To create your own collections, you must have a Mozilla Add-ons account.