Garbled non-ascii latin characters in iOs contacts

[purung]

Having successfully created a carddav account on iOs, I found that certain Swedish characters were garbled in the output. This is true for both contact names and other attributes in the vCard, such as addresses. No such bug is present in Thunderbird on macOs or Contact app on Android. Is this a known problem? Is there any Stalwart or iOs setting that fixes it?

I should add that the problem is not present on the CalDav account created on the same device. Calendar strings are not garbled.

Reference output:

Örjan Ärling -> örjan ärling

[purung]

If anyone else encounters this, I solved it by converting my address book to vCard 3.0. It turns out that Apple erroneously guesses a Latin-1 encoding for vCard 4.0 entries without an explicit charset.