The abbreviation IDN (=Interrnationalized Domain Name) refers to domains that contain umlauts, special characters or letters from alphabets other than the Latin alphabet. Generally, these are also called umlaut or special character domains. If an SSL certificate is issued IDN-compatible, this means that this certificate can be used for an IDN domain.
Our EuropeanSSL certificates are compatible with IDN domains. To do this, enter the domain name as an ACE string when generating the CSR, such as xn--zz-viaa.de for the IDN domain zääz.de. If you generate the CSR using our CSR generator, the conversion is done automatically and you don't need to do anything else.