I would like to use ECDSA certificates for user authentication in SoftEther VPN. When using vpncmd, importing the root CA works correctly. However, when I try to import my ECDSA certificate along with its private key, I receive error messages on both the client and server sides.

Error occurred. (Error code: 77)
The specified X509 certificate file does not contain a RSA 1024 bit or 2048 bit public key.
SoftEther VPN software supports only RSA 1024 bit or 2048 bit certificates.

I found the following related issues:
#1034
#475

According to the README.txt, ECDSA certificate import is supported in the development version. I have tested this using version 5.02.5187 as well as the current master (commit 48042cf). But both return the mentioned error.

Is user authentication using ECDSA certificates still not supported?