This version of OpenVPN has mbed TLS support. To enable, follow the instructions below: To build and install, ./configure --with-crypto-library=mbedtls make make install This version requires mbed TLS version >= 2.0.0 or >= 3.2.1. ************************************************************************* Due to limitations in the mbed TLS library, the following features are missing in the mbed TLS version of OpenVPN: * PKCS#12 file support * --capath support - Loading certificate authorities from a directory * Windows CryptoAPI support * X.509 alternative username fields (must be "CN") Plugin/Script features: * X.509 subject line has a different format than the OpenSSL subject line * X.509 certificate tracking ************************************************************************* Mbed TLS 3 has implemented TLS 1.3, but support in OpenVPN requires the function mbedtls_ssl_export_keying_material() which is currently not in any released version. It is available when building mbed TLS from source (mbedtls-3.6 or development branch). Without this function, only TLS 1.2 is available.