Cannot open /etc/dhparam/dh-default.pem for DH parameters

After automatic upgrade to TOS 5.2 (and manual reboot), the OpenVPN server could no longer start and issued these messages:

OpenSSL: error:02001002:system library:fopen:No such file or directory
OpenSSL: error:2006D080:BIO routines:BIO_new_file:no such file
Cannot open /etc/dhparam/dh-default.pem for DH parameters

As I could see, the /etc/dhparam/dh-default.pem file was not present although the configuration file (openvpn-server_turris.conf) refered to it. There was only /etc/dhparam/dh2048.pem and /usr/share/turris-cagen/dhparam.pem. Copying the latter one to /etc/dhparam/dh-default.pem helped to start the server.

Edited by Lukas Jelinek
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