I generated a VCF file from my Galaxy A7 2017 phone, using latest version pf Android. In the Web interface of nextcloud (hostiso provider), I select to import all contacts from that file. A window is show with a progress bar indicating some type of processing is taking place, yet after doing it, nothing is imported…
For all who might sumble across this issue as I did…
I had a message in the logs of my v25 instance that CardDAV servers do not support VCard format 2.1.
To “update” to a modern format, I used Thunderbird:
Import the .vcf into a seperate Thunderbird address book.